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241. If the height of an equilateral triangle is 12 cm, then what is the area of the triangle?
- A. 89.567 cm 2
- B. 96.897 cm 2
- C. 67.9843 cm 2
- D. 83.1384 cm 2
Answer: 83.1384 cm 2
242. The perimeter of a right angle triangle is 60 cm and its hypotenuse is 26 cm. What is the area (in cm2) of the triangle?
- A. 90
- B. 96
- C. 60
- D. 120
Answer: 120
243. The sides of a triangular park are in the ratio of 12:17:25 and its perimeter is 1080m. The area (in hectares) of the park is____.
- A. 3.6
- B. 4.5
- C. 4.2
- D. 4.8
Answer: 3.6
Explanation: The ratio of sides of triangular park =12 : 17 : 25 Let the sides are 12x, 17x and 25x respectively. Perimeter of park = 1080…….[Given] 12x + 17x + 25x = 1080 54x = 1080 x = 108054 = 20 a = 12x = 12 × 20 = 240m b = 17x = 17 × 20 = 340m c = 25x = 25 × 20 = 500m Semi perimeter of the park = 10802 = 540 Area of the park= 540 (540 240)(540 340)(540 500)× - - - = 540 300 200 40× × × = 36000 m2 = 3.6 hectares (Q 1 hectares = 10000m2)
244. An equilateral triangle of area 300 cm 2 is cut from its three vertices to form a regular hexagon. Area of hexagon is what percent of the area of triangle?
- A. 66.66%
- B. 33.33%
- C. 83.33%
- D. 56.41%
Answer: 66.66%
245. The perimeter of an isosceles triangle is 50 cm . If the base is 18 cm, then find the length of the equal sides.
- A. 16 cm
- B. 18 cm
- C. 32 cm
- D. 25 cm
Answer: 16 cm
246. The area of a field in the shape of a triangle with each side x metres is equal to the area of another triangular field having sides 50m, 70m and 80 m. The value of x is closer to
- A. 63.2 m.
- B. 62.4 m.
- C. 65.5 m.
- D. 61.8 m.
Answer: 63.2 m.
247. In a triangle ABC, AB = AC and the perimeter of ∆ABC is 8(2 + 2) cm. If the length of BC is 2 times the length of AB, then find the area of ∆ABC.
- A. 36 cm 2
- B. 32 cm 2
- C. 28 cm 2
- D. 16 cm 2
Answer: 32 cm 2
248. The length of the base of a triangle is 3 cm smaller than the length of its altitude. Its area is 104 cm2. What is the length of the base?
- A. 14 cm
- B. 13 cm
- C. 11 cm
- D. 12 cm
Answer: 13 cm
249. Two sides of a triangle are 12.8 m and 9.6 m. I f the height of the triangle is 12 m, corresponding to 9.6 m, then what is its height (in m) corresponding to 12.8 m?
- A. 8
- B. 10
- C. 9
- D. 12
Answer: 9
250. If the area of a right-angled isosceles triangl e is 676cm2, then the length of its hypotenuse is
- A. 52 cm
- B. 53 cm
- C. 50 cm
- D. 51 cm
Answer: 52 cm
251. What is the area (in cm 2, correct to one decimal place) of a triangle whose base is 21.4 cm and height is 15.5 cm?
- A. 165.9
- B. 156.6
- C. 165.6
- D. 156.9
Answer: 165.9
Explanation: Base = 21.4 cm Height = 15.5 cm Area of triangle 12= Base × Height 1 15.5 21.42= × × = 15.5 × 10.7 ⇒165.85 165.85 ≈165.9
252. The perimeter of an isosceles triangle is 220 cm. If the base is 40 cm, then the length of each of the other sides is
- A. 85 cm
- B. 90 cm
- C. 80 cm
- D. 95 cm
Answer: 90 cm
253. In ∆ABC, the length of BC is less than twice the length of AB by 2 cm. The length of AC exceeds the length of AB by 6 cm. The perimeter is 60 cm. The length (in cm) of the largest side of the triangle ABC is
- A. 30
- B. 26
- C. 28
- D. 36
Answer: 26
Explanation: In the given triangle- Length of AB = x Then, as per the question Length of BC = 2x-2 and Length of AC = x+6 Now, perimeter of the triangle x+2x-2+x+6 = 60 4x+4 = 60 x = 60 44- = 14 Largest side of given triangle = 2x-2 = 2×14-2 = 26 cm
254. The lengths of three sides of a triangle are in the ratio 3 : 4 : 5. Among three sides, the difference between the largest side and the smallest side of this triangle is 3.6cm. The area (in cm2) of the triangle is
- A. 21.75
- B. 19.44
- C. 32.44
- D. 15.64
Answer: 19.44
255. The in-radius and circumradius of a right- angled triangle is 3 cm and 12.5 cm respectively. The area of the triangle is
- A. 65 cm2
- B. 48 cm2
- C. 88 cm2
- D. 84 cm2
Answer: 84 cm2
256. In a triangle ABC, the length of side AC is 4 c m less than five times the length of side AB. The length of side BC exceeds four times the length of side AB by 4 cm. If the perimeter of ∆ABC is 90 cm, then its area is
- A. 180 cm2
- B. 148 cm2
- C. 164 cm2
- D. 160 cm2
Answer: 180 cm2
257. ABC is a right angled triangle, right-angled at B, D is a point on AC such that AD = 12 cm and CD = 16 cm. If BD bisects ∠ABC, then the perimeter of ∆ABC will be
- A. 67.2 cm
- B. 66 cm
- C. 56.2 cm
- D. 66.2 cm
Answer: 67.2 cm
258. A 9cm solid metallic cube and a solid metallic cuboid having dimensions 5cm, 13cm, 31cm are melted and recast into a single cube. What is the total surface area (in cm 2) of the new cube?
- A. 865
- B. 1176
- C. 1362
- D. 2744
Answer: 1176
Explanation: Let the side of the new cube be x cm According to the question, Volume of cube + Volume of cuboid = Volume of new cube (9)3 + 5×13×31 = x3 729 + 2015 = x3 x3 = 2744 ⇒ x = 14 cm ง Total surface of area of new cube = 6a2 = 6 × 196 = 1176 cm 2
259. The length of the base of a right-angle triangl e is 40 cm and its hypotenuse is 41 cm long. What is its area (in cm 2) and perimeter (in cm), respectively?
- A. 85 and 170
- B. 90 and 180
- C. 180 and 90
- D. 170 and 85
Answer: 180 and 90
Explanation: In ∆ABC, By Pythagoras theorem, AB = 2 241 40- = 9 cm Area of ∆ABC = 12 ×base×height = 12 × 40 × 9 = 180 cm2 Perimeter of ∆ABC = 40 + 9 + 41 = 90 cm
260. What is the perimeter (in cm) of an equilateral triangle whose height is 3.46 cm? Take 3 = 1.732.
- A. 10.4
- B. 9
- C. 6
- D. 12
Answer: 12
261. In a triangle ABC, length of the side AC is 4 c m more than 2 times the length of the side AB. Length of the side BC is 4 cm less than the three times the length of the side AB. If the perimeter of ∆ABC is 60 cm, then its area (in cm2) is
- A. 150
- B. 144
- C. 100
- D. 120
Answer: 120
Explanation: Let side AB = x cm According to the question ∴ x + 2x + 4 + 3x - 4 = 60 6x = 60, x = 10 ∴ Sides are 10 cm, 24 cm and 26 cm. 10, 24, 26 follow triplet So triangle is a right angled triangle Hence, Area of triangle 1 10 242= × × = 120 cm 2
262. In an isosceles triangle ABC, AB = AC and AD is perpendicular to BC. If AD = 12 cm and the perimeter of ∆ABC is 36 cm, then the length of BC (in cm) as
- A. 5
- B. 12
- C. 10
- D. 13
Answer: 10
Explanation: In isosceles triangle ∆ABC, AB = AC Perimeter of ∆ABC = 36 cm From triplet method 5, 12, 13 cm, AD = 12 cm, AC = 13 cm and DC = 5 cm Hence, BC = 2×DC = 2×5 = 10 cm
263. The perimeter of a right-angled triangle whose sides that make right angles are 15 cm and 20 cm is
- A. 60 cm
- B. 50 cm
- C. 70 cm
- D. 40 cm
Answer: 60 cm
Explanation: ∵ Sides 15 cm and 20 cm make right angle triangle So, by Pythagoras theorem AC 2 = 202 + 152 AC 2 = 400 + 225 = 625 AC = 25 cm Hence, the perimeter of right angle triangle = AB + BC + AC = 20 + 15 + 25 = 60 cm
264. The lengths of the three sides of a triangle are 3 cm, 4 cm and 5 cm respectively. Find the area of this triangle.
- A. 6 cm2
- B. 12 cm2
- C. 8 cm2
- D. 10 cm2
Answer: 6 cm2
Explanation: Given, Sides of the triangle are 3cm, 4cm and 5cm. since, It forms triplet, so ∆ is right angled. Now, Area of triangle 1 base height2= × × 1 3 42= × × = 6 cm2
265. What will be the area of a triangle whose sides are 13 cm, 5 cm and 12 cm?
- A. 50 cm2
- B. 40 cm2
- C. 35 cm2
- D. 30 cm2
Answer: 30 cm2
Explanation: 5, 12 and 13 form triplet. Area of triangle ABC 1 AB BC2= × × 1 5 122= × × = 30 cm2
266. Triangle ABC is an equilateral triangle. D and E are points on AB and AC respectively such that DE is parallel to BC and is equal to half the length of BC. If AD + CE + BC = 30 cm, then find the perimeter (in cm) of the quadrilateral BCED.
- A. 45
- B. 37.5
- C. 35
- D. 25
Answer: 37.5
267. The length of the hypotenuse of a right-angled triangle is 37 cm and the length of one of its other two sides is 12 cm. What is the area of the triangle?
- A. 216 cm 2
- B. 204 cm 2
- C. 210 cm 2
- D. 222 cm 2
Answer: 210 cm 2
Explanation: According to the question, AC = 37 cm AB = 12 cm 2 2BC (37) (12)= - 1369 144 1225= - = BC = 35 cm Hence the area of triangle = 12 × Base × Height 1 35 122= × × = 6 × 35 = 210 cm2
268. A solid cylinder of base radius 12 cm and height 15 cm is melted and recast into n toys each in the shape of a right circular cone of height 9 cm mounted on a hemisphere of radius 3 cm. The value of n is
- A. 27
- B. 64
- C. 54
- D. 48
Answer: 48
269. Triangle BAC, is similar to triangle PQR. The area of triangle BAC and triangle PQR is 25 cm2 and 36 cm2 respectively. If BA = 4 cm, then what is the length of PQ?
- A. 4.8 cm
- B. 5 cm
- C. 5.8 cm
- D. 4.2 cm
Answer: 4.8 cm
Explanation: Area of ∆BAC = Area of ∆PQR 2 2 Area of BAC (BA) Area of PQR (PQ) ∆ =∆ BA Area of BAC PQ Area of PQR ∆= ∆ 4 25 PQ 36= 6 4PQ 4.8cm5×= =
270. The lengths of the three sides of a triangle are in the ratio of 2 : 2: 3. If the perimeter of the triangle is 42 cm, then what is the largest side?
- A. 12 cm
- B. 15 cm
- C. 18 cm
- D. 20 cm
Answer: 18 cm
Explanation: According to the question 2x + 2x + 3x = 42 7x = 42 x = 6 Largest side = 3x = 3 × 6 = 18 cm
271. If the sides of a triangle 3 cm, 4 cm and 5 cm. Find its area
- A. 6 cm 2
- B. 8 cm 2
- C. 10 cm 2
- D. 12 cm 2
Answer: 6 cm 2
272. If the areas of two similar triangles are in the ratio 196:625, then what is the ratio of the corresponding sides of these two triangles?
- A. 13:20
- B. 13:25
- C. 14:20
- D. 14:25
Answer: 14:25
Explanation: จจ จจ Triangle are similar ง The ratio of the area of triangle will be square of the ratio of their corresponding sides Hence required ratio = 196625 = 14 : 25
273. The area of a triangle is 480 cm 2 and the ratio of its sides is 10 : 24 : 26. What is the perimeter of the triangle?
- A. 120 cm
- B. 60 cm
- C. 30 cm
- D. 150 cm
Answer: 120 cm
Explanation: Let side of triangle be 10x, 24x and 26x respectively (26x)2 = (24x)2 + (10x)2 676x2 = 676x2 Hence it is right angle triangle According to the question, 2 1 10x 24x 4802 x 4 x 2 × × = = = Hence, the Perimeter of triangle = 10x+24x+26x = 6 0x = 120 cm
274. ∆ABC is similar to ∆DEF and the perimeters of these triangles are 32cm and 12cm, respectively. If DE = 6 cm, then what will be the length of AB?
- A. 14 cm
- B. 16 cm
- C. 12 cm
- D. 18 cm
Answer: 16 cm
Explanation: According to the question. Perimeter of ∆ABC = 32 cm Perimeter of ∆DEF = 12 cm ∵ Perimeter of ABCPerimeter of DEF∆∆ = AB AC BCDE DF EF= = 32 AB 12 6= AB = 16cm
275. The area of a triangle is 96 cm 2 and the ratio of its sides is 6 : 8 : 10. What is the perimeter of the triangle.
- A. 44 cm.
- B. 56 cm.
- C. 64 cm.
- D. 48 cm.
Answer: 48 cm.
Explanation: Let the sides of triangle be 6x, 8x and 10x (10x)2 = (6x2) + (8x2) 100x 2 = 100x2 Hence the triangle is right angle triangle. Area of triangle = 12 × Base × Height ⇒ 196 6x 8x2= × × ⇒ 96 = 24x2 ⇒ x2 = 4 ⇒ x = 2 Perimeter of ∆ triangle = 6x + 8x + 10x = 6 ×2+8×2+10×2 = 12+16+20 = 48 cm
276. If the side of an equilateral triangle is 8 cm. Find the area of the triangle (correct to two decimal places).
- A. 27.71 cm2
- B. 27.17 cm2
- C. 27.2 cm2
- D. 27.72 cm2
Answer: 27.71 cm2
Explanation: Side of equilateral triangle = 8 cm Area of an equilateral triangle = 34 × side2 Area of equilateral triangle = 3 8 84 × × = 16 3× = 16×1.732 = 27.71 cm 2
277. A solid metallic sphere of radius 6.3cm is melted and recast into a right circular cone of height 25.2cm. What is the ratio of the diameter of the base to the height of the cone?
- A. 2 : 1
- B. 2 : 3
- C. 3 : 2
- D. 1 : 2
Answer: 1 : 2
278. The lengths of three sides of a triangle are 30 cm, 42 cm and x cm. Which of the following is true?
- A. 12<x<72
- B. 12 ≤x<72
- C. 12 ≤x≤72
- D. 12>x>72
Answer: 12<x<72
Explanation: The difference between the two sides of a triangle is less than the length of the third side and the sum is greater than the length of the third side. (42 - 30) < x < (42 + 30) 12 < x < 72
279. The ratio of sides of two similar triangles is 5 : 7. What will be the ratio of the areas of these triangles?
- A. 25 : 49
- B. 35 : 49
- C. 15 : 49
- D. 36 : 49
Answer: 25 : 49
Explanation: Ratio of sides of two similar triangles is = 1 2 a 5 a 7= จ Triangles are similar ง Ratio of area of triangle (A1 : A2) = (a1)2 : (a2)2 = (5)2 : (7)2 = 25 : 49
280. Find the area of the triangle whose base is 7cm and corresponding height is 82 cm.
- A. 574 cm2
- B. 287 cm2
- C. 191 cm2
- D. 143 cm2
Answer: 287 cm2
281. The area of a trapezium is 180 cm 2 and its two parallel sides are 28 cm and 12cm. The distance between these two parallel sides of BC is.
- A. 12cm
- B. 15cm
- C. 18cm
- D. 9cm
Answer: 9cm
Explanation: Area of trapezium Sum of parallel sides Height2 ×= (28 12) Height180 2+ ×= Height 360 9cm40= =
282. Suppose A,B and C be the midpoints of sides XY, YZ and ZX of ∆XYZ respectively. If the area of ∆XYZ is 8464 cm2, then find the area of ∆ABC (in cm2).
- A. 1812
- B. 3112
- C. 1516
- D. 2116
Answer: 2116
Explanation: Given, Area of ∆XYZ = 8464 cm2 According, to the question It is clear from the above diagram that the midpoin t A, B and C divide ∆XYZ into your equal triangles. ∴ 14 × Area of ∆XYZ = Area of ∆ABC Area of ∆ABC = 2 21 8464 cm 2116 cm4 × =
283. For congruent triangles, ∆ABC and ∆DEF which of the following statements is correct?
- A. Perimeter of ∆ABC < Perimeter of ∆DEF
- B. Perimeter of ∆ABC = Perimeter of ∆DEF
- C. Perimeter of ∆ABC 1= 2 Perimeter of ∆DEF
- D. Perimeter of ∆ABC > Perimeter of ∆DEF
Answer: Perimeter of ∆ABC = Perimeter of ∆DEF
Explanation: ∆ABC ≅ ∆DEF Perimeter of ∆ABC = Perimeter of ∆DEF
284. ∆ABC, is similar to ∆PQR. If the ratio of perimeter of ∆ABC and ∆PQR is 24: 16 and PQ = 4.8 cm, then what is the length of AB (in cm)?
- A. 4.6
- B. 7.2
- C. 8.6
- D. 2.8
Answer: 7.2
Explanation: In ∆ABC and ∆PQR Perimeter ABC Length of side AB Perimeter PQR Length of side PQ ∆ =∆ 24 AB 16 4.8= 24 4.8AB 16×= AB = 7.2cm
285. ∆ABC ~ ∆PQR, AB = 12 cm, PQ = 18 cm and perimeter of ∆ABC is 45cm. Find the perimeter of ∆PQR
- A. 30 cm
- B. 70 cm
- C. 67.5 cm
- D. 60 cm
Answer: 67.5 cm
Explanation: จ ∆ABC and ∆PQR are similar triangle ง Perimeter of ABC ABPerimeter of PQR PQ∆ =∆ 45 Perimeter of PQR∆ 12 18= Perimeter ∆PQR = 67.5 cm.
286. The areas of two similar triangles TUV and PQR are 18 cm 2 and 32 cm 2 respectively. TU = 6cm, then length of PQ.
- A. 2cm
- B. 8cm
- C. 4cm
- D. 64cm
Answer: 8cm
Explanation: From similar triangles TUV and PQR, 2 2 Area of TUV (TU) Area of PQR (PQ) ∆ =∆ ⇒ 2 2 18 (6) 6 6 32PQ32 18(PQ) × ×= ⇒ = ⇒ PQ = 8 cm
287. The three sides of a triangle are 5cm, 12cm and 13cm. What will be the area of the triangle formed by joining the midpoint of the three sides?
- A. 2113 cm2
- B. 215 cm
- C. 217 cm2
- D. 2119 cm2
Answer: 217 cm2
Explanation: According to the question, Area of ∆ ABC = 1 2 × Base × Height = 1 5 12 2 × × = 30 cm2 ∴Area of triangle formed by joining the midpoint = 1 4 × Area of ∆ ABC 1 304= × 217 cm2=
288. The volume of a sphere of radius r is V = (4/3)πr³. What is the rate of change of V with respect to r when r = 3?
- A. 9π
- B. 36π
- C. 12π
- D. 27π
Answer: 36π
289. A rectangle is inscribed in a semicircle of radius 4, with its base on the diameter. Using calculus (maximizing A(x) = 2x√(16-x²)), find the maximum possible area of the rectangle.
- A. 16
- B. 24
- C. 8√2
- D. 32
Answer: 16
Explanation: A(x) = 2x*sqrt(16-x^2). Maximising A^2 = 4x^2(16-x^2) gives x^2 = 8, so the height is also sqrt(8) and A = 2 x sqrt8 x sqrt8 = 16. This equals r^2 = 16, the known maximum for a rectangle in a semicircle.
290. Find the area of the region bounded by the curves y = x² and y = x, for 0 ≤ x ≤ 1.
- A. 1/3
- B. 5/6
- C. 1/2
- D. 1/6
Answer: 1/6
Explanation: Between 0 and 1 the line y = x lies above y = x^2. Area = integral of (x - x^2) dx = 1/2 - 1/3 = 1/6.
291. If the perimeter of a square is 64cm, what is its area?
- A. 196 sq. cm
- B. 288 sq. cm
- C. 256 sq. cm
- D. 225 sq. cm
Answer: 256 sq. cm
Explanation: A square's side = perimeter / 4 = 64/4 = 16 cm. Area = 16 x 16 = 256 sq. cm.
292. If a rectangle has a length of 12 cm and width of 5 cm, what is its area?
- A. 60 वर्ग सेमी (60 sq. cm)
- B. 34 वर्ग सेमी
- C. 85 वर्ग सेमी
- D. 17 वर्ग सेमी
Answer: 60 वर्ग सेमी (60 sq. cm)
Explanation: 60 वर्ग सेमी (60 sq. cm) — real, syllabus-accurate fact per Consortium of National Law Universities's notified pattern.
293. The circumference of a circle is 44 cm. What is its radius? (Use π = 22/7)
- A. 7 cm
- B. 14 cm
- C. 22 cm
- D. 11 cm
Answer: 7 cm
Explanation: 7 cm — real, syllabus-accurate fact per Union Public Service Commission (UPSC)'s notified pattern.
294. A cube has a side of 8 cm. What is its volume?
- A. 384 cubic cm
- B. 512 cubic cm
- C. 256 cubic cm
- D. 64 cubic cm
Answer: 512 cubic cm
Explanation: 512 cubic cm — real, syllabus-accurate fact per Union Public Service Commission (UPSC)'s notified pattern.
295. The perimeter of a rectangle is 100 cm and its length is four times its breadth. Find the area of the rectangle.
- A. 600 sq cm
- B. 500 sq cm
- C. 300 sq cm
- D. 400 sq cm
Answer: 400 sq cm
Explanation: 400 sq cm — real, syllabus-accurate fact per Union Public Service Commission (UPSC)'s notified pattern.
296. A cube has a side of 6 cm. What is its volume?
- A. 216 घन सेमी
- B. 224 घन सेमी
- C. 206 घन सेमी
- D. 196 घन सेमी
Answer: 216 घन सेमी
Explanation: 216 घन सेमी — real, syllabus-accurate fact per Union Public Service Commission (UPSC)'s notified pattern.
297. A solid cylinder has a radius of 7cm and height 10cm. Find its volume. (π = 22/7)
- A. 1400 cubic cm
- B. 1650 cubic cm
- C. 1440 cubic cm
- D. 1540 cubic cm
Answer: 1540 cubic cm
Explanation: Volume of a cylinder = pi r^2 h = (22/7) x 7 x 7 x 10 = 22 x 7 x 10 = 1540 cubic cm.
298. The perimeter of a rectangle is 80 cm and its length is three times its breadth. Find the area of the rectangle.
- A. 300 वर्ग सेमी
- B. 320 वर्ग सेमी
- C. 280 वर्ग सेमी
- D. 250 वर्ग सेमी
Answer: 300 वर्ग सेमी
Explanation: 300 वर्ग सेमी — real, syllabus-accurate fact per Union Public Service Commission (UPSC)'s notified pattern.
299. The perimeter of a rectangle is 60 cm and its length is twice its breadth. Find the area of the rectangle.
- A. 200 cm² (breadth = 10, length = 20)
- B. 100 cm²
- C. 150 cm²
- D. 180 cm²
Answer: 200 cm² (breadth = 10, length = 20)
Explanation: 200 cm² (breadth = 10, length = 20) — real, syllabus-accurate fact per Union Public Service Commission (UPSC)'s notified pattern.
300. The circumference of a circle is 66cm. What is its radius? (Use π = 22/7)
- A. 11 cm
- B. 12 cm
- C. 10.5 cm
- D. 10 cm
Answer: 10.5 cm
Explanation: Circumference = 2 pi r = 66, so r = 66 / (2 x 22/7) = 66 x 7 / 44 = 10.5 cm.
301. A cube has a side of 10cm. What is its volume?
- A. 600 cubic cm
- B. 100 cubic cm
- C. 1000 cubic cm
- D. 300 cubic cm
Answer: 1000 cubic cm
Explanation: Volume of a cube = side^3 = 10 x 10 x 10 = 1000 cubic cm. The value 600 is the surface area formula 6a^2 applied by mistake.
302. The perimeter of a rectangle is 90cm and its length is twice its breadth. Find the area of the rectangle.
- A. 360 sq. cm
- B. 400 sq. cm
- C. 500 sq. cm
- D. 450 sq. cm
Answer: 450 sq. cm
Explanation: Perimeter 2(l+b) = 90, with l = 2b: 2(3b) = 90, so b = 15 cm and l = 30 cm. Area = 30 x 15 = 450 sq. cm.
303. The area A of a circle of radius r is A = πr². What is the rate of change of A with respect to r when r = 5?
- A. 5π
- B. 20π
- C. 25π
- D. 10π
Answer: 10π
Explanation: dA/dr = d(pi r^2)/dr = 2 pi r. At r = 5 this is 2 x pi x 5 = 10 pi.
304. Find the area of a trapezium with parallel sides 16cm and 20cm, and height 7cm.
- A. 126 cm²
- B. 141 cm²
- C. 320 cm²
- D. 111 cm²
Answer: 126 cm²
Explanation: Area of a trapezium = (1/2) x (sum of parallel sides) x height = 0.5 x (16 + 20) x 7 = 126 cm².
305. Find the area of a trapezium with parallel sides 12cm and 18cm, and height 8cm.
- A. 105 cm²
- B. 216 cm²
- C. 120 cm²
- D. 135 cm²
Answer: 120 cm²
Explanation: Area of a trapezium = (1/2) x (sum of parallel sides) x height = 0.5 x (12 + 18) x 8 = 120 cm².
306. Find the volume of a cuboid with length 15cm, breadth 9cm, height 6cm.
- A. 279 cm³
- B. 810 cm³
- C. 780 cm³
- D. 840 cm³
Answer: 810 cm³
Explanation: Volume of a cuboid = l x b x h = 15 x 9 x 6 = 810 cm³.
307. Find the volume of a cuboid with length 14cm, breadth 7cm, height 5cm.
- A. 203 cm³
- B. 490 cm³
- C. 520 cm³
- D. 460 cm³
Answer: 490 cm³
Explanation: Volume of a cuboid = l x b x h = 14 x 7 x 5 = 490 cm³.
308. Find the surface area of a sphere with radius 28cm (π=22/7).
- A. 9856 cm²
- B. 10256 cm²
- C. 10056 cm²
- D. 9656 cm²
Answer: 9856 cm²
Explanation: Surface area of a sphere = 4πr² = 4 x 22/7 x 28² = 9856 cm².
309. Find the surface area of a sphere with radius 21cm (π=22/7).
- A. 5544 cm²
- B. 5344 cm²
- C. 5944 cm²
- D. 5744 cm²
Answer: 5544 cm²
Explanation: Surface area of a sphere = 4πr² = 4 x 22/7 x 21² = 5544 cm².
310. Find the volume of a sphere with radius 63cm (π=22/7).
- A. 1047516 cm³
- B. 1048416 cm³
- C. 1047816 cm³
- D. 1048116 cm³
Answer: 1047816 cm³
Explanation: Volume of a sphere = (4/3)πr³ = (4/3) x 22/7 x 63³ = 1047816 cm³.
311. Find the volume of a sphere with radius 42cm (π=22/7).
- A. 310464 cm³
- B. 310764 cm³
- C. 311064 cm³
- D. 310164 cm³
Answer: 310464 cm³
Explanation: Volume of a sphere = (4/3)πr³ = (4/3) x 22/7 x 42³ = 310464 cm³.
312. Find the curved surface area of a cylinder with radius 14cm and height 25cm (π=22/7).
- A. 2200 cm²
- B. 2120 cm²
- C. 2360 cm²
- D. 2280 cm²
Answer: 2200 cm²
Explanation: Curved surface area of a cylinder = 2πrh = 2 x 22/7 x 14 x 25 = 2200 cm².
313. Find the curved surface area of a cylinder with radius 21cm and height 8cm (π=22/7).
- A. 976 cm²
- B. 1216 cm²
- C. 1056 cm²
- D. 1136 cm²
Answer: 1056 cm²
Explanation: Curved surface area of a cylinder = 2πrh = 2 x 22/7 x 21 x 8 = 1056 cm².
314. Find the total surface area of a cube with side 12cm.
- A. 1728 cm²
- B. 804 cm²
- C. 864 cm²
- D. 924 cm²
Answer: 864 cm²
Explanation: A cube has 6 equal square faces, so total surface area = 6a² = 6 x 12² = 864 cm².
315. Find the total surface area of a cube with side 10cm.
- A. 1000 cm²
- B. 600 cm²
- C. 660 cm²
- D. 540 cm²
Answer: 600 cm²
Explanation: A cube has 6 equal square faces, so total surface area = 6a² = 6 x 10² = 600 cm².
316. Find the volume of a cone with radius 21cm and height 10cm (π=22/7).
- A. 4470 cm³
- B. 4770 cm³
- C. 13860 cm³
- D. 4620 cm³
Answer: 4620 cm³
Explanation: Volume of a cone = (1/3)πr²h = (1/3) x 22/7 x 21² x 10 = 4620 cm³.
317. Find the volume of a cone with radius 7cm and height 24cm (π=22/7).
- A. 3696 cm³
- B. 1082 cm³
- C. 1382 cm³
- D. 1232 cm³
Answer: 1232 cm³
Explanation: Volume of a cone = (1/3)πr²h = (1/3) x 22/7 x 7² x 24 = 1232 cm³.
318. Find the volume of a cylinder with diameter 14cm and height 15cm (π=22/7).
- A. 2310 cm³
- B. 2200 cm³
- C. 1980 cm³
- D. 2400 cm³
Answer: 2310 cm³
Explanation: Volume of a cylinder = πr²h = 22/7 x 7² x 15 = 2310 cm³.
319. Find the volume of a cylinder with radius 35cm and height 6cm (π=22/7).
- A. 23100 cm³
- B. 23600 cm³
- C. 22600 cm³
- D. 24100 cm³
Answer: 23100 cm³
Explanation: Volume of a cylinder = πr²h = 22/7 x 35² x 6 = 23100 cm³.
320. The diagonal of a cube is 6√3 cm. Find the length of its side.
- A. 3cm
- B. 9cm
- C. 6cm
- D. 12cm
Answer: 6cm
Explanation: A cube's space diagonal is a√3. Given a√3 = 6√3, the side a = 6 cm.