CBSE Class 8 Mathematics Mensuration Assignment Set A

 Mensuration

Question. Three cubes of metal whose edges are in the ratio 3 : 4 : 5 are melted down into a single cube whose diagonal is 12 3 cm. Find the edge of smallest of the three given cubes.
(a) 6 cm
(b) 7 cm
(c) 8 cm
(d) 9 cm

Answer: A

Question. The area of two circular fields is in the ratio 16 : 49. If the radius of the latter is 14 m, what is the radius of the former?
(a) 32 m
(b) 18 m
(c) 8 m
(d) 4 m

Answer: A

Question. The radii of the two cylinders are in the ratio 2 : 3 and their heights are in the ratio 5 : 3. What is the ratio of their volumes?
(a) 20 : 27
(b) 18 : 27
(c) 15 : 21
(d) 11 : 15

Answer: D

Question. The volume of the metallic cylindrical pipe is 748 cm³ . Its length is 14 cm and its external radius is 9 cm. Find its thickness.
(a) 4
(b) 3
(c) 2
(d) 1

Answer: D

Question. Find the number of coins 1.5 cm in diameter and 0.2 cm thick to be melted to form a right circular cylinder whose height is 8 cm and diameter 6 cm.
(a) 620
(b) 640
(c) 660
(d) 680

Answer: B

Question. The inside circumference of a circular field is 1188 m. A road 7 m wide is constructed on the outside. Find its area.
(a) 8070 m²
(b) 8270 m²
(c) 8370 m²
(d) 8470 m²

Answer: D

Question. A piece of metal in the form of a cone of radius 3 cm and height 7 cm melted and cast into a cube. Find the side of cube (nearest to a whole number)
(a) 5 cm
(b) 4' cm
(c) 3 cm
(d) 2 cm

Answer: B

Question. A room is 15 metres long, 4 metres broad and 3 metres high. Find the cost of white washing its four walls at 50 P. per m² . '
(a) Rs. 60
(b) Rs. 57
(c) Rs.55
(d) Rs. 52

Answer: B

Question. How much paint is required for painting the outer surface of the water tank 2 m × 4 m × 3 m if it needs 1/6 of a litre for every m2?
(a) 16 litres
(b) 15 litres
(c) 12 litres
(d) 10 litres

Answer: C

Question. Three solid spheres of gold whose radii are 1 cm, 6 cm and 8 cm respectively are melted into a single solid sphere. Find the radius of the sphere.
(a) 6 cm
(b) 7 cm
(c) 8 cm
(d) 9 cm

Answer: D

Question. The vertical height of a conical tent is 42 dm and its diameter of the base is 54 dm. How many persons can it accommodate if each person is to be allowed 2916 dm³ of space? (π = 22/7)
(a) 11
(b) 10
(c) 9
(d) 8

Answer: A

Question. If the radius of the base of the right circular cylinder is reduced by 50%, keeping the same height, what is the ratio of the volume of the reduced cylinder to that of the original.
(a) 1 : 9
(b) 1 : 8
(c) 1 : 4
(d) 1 : 2

Answer: C

Question. It needs 50 ml paint for painting a picture 50 cm × 25 cm. How much paint is needed to paint a similar picture 100 cm × 50 cm?
(a) 100 ml
(b) 400 ml
(c) 750 ml
(d) 200 ml

Answer: D

Question. What is the length of the greatest rod that can be placed in a room whose length is 10 m, breadth 8 m and height 6 m. Given that 2 = 1.42 .
(a) 13.2
(b) 14.2
(c) 15.2
(c) 16.2

Answer: B

Question. The sides of a rectangular plot are in the ratio of 4 : 3 and its area is 1452 m² . Find the cost of fencing it at Rs 2.50 P per metre.
(a) Rs. 480
(b) Rs. 385
(c) Rs.375
(d) Rs. 365

Answer: B

Question. The area of four walls of a room is 120 m² and its length is twice the breadth, the height being 4 metres. Find the area of the floor.
(a) 50 m²
(b) 60 m²
(c) 75 m²
(d) 100 m²

Answer: A

Question. The edge of three iron cubes are 6 cm, 8 cm, 10 cm respectively. A new cube was made by melting them. Find the edge of the new cube.
(a) 8
(b) 12
(c) 14
(d) 10

Answer: B

Question. Find the cost of fencing a circular field at the rate of 50 P. per metre if its area is 13860 m² . (π = 22/7)
(a) Rs. 660
(b) Rs.540
(c) Rs. 700
(d) Rs. 800

Answer: A

Question. Two cubes, each of edge 12 cm are joined end to end. Find the surface area of resulting cuboid.
(a) 1450 cm²
(b) 1440 cm²
(c) 1420 cm²
(c) 1410 cm²

Answer: B

Question. What is the radius of a circular field whose area is equal to the sum of the areas of the three circular fields with radii 4 m, 4.5 m and 6 m respectively?
(a) 9 m
(b) 10.5 m
(c) 10 m
(d) 8.5 m

Answer: D

Question. A right circular cylinder and a right circular cone have equal bases and equal heights. If their curved surfaces are in the ratio 8 : 5, what is the ratio of their base to their heights?
(a) 3 : 4
(b) 5 : 4
(c) 6 : 7
(d) 9 : 8

Answer: A

Question. If all the sides of a triangle be increased by 200 percent what is the corresponding increase in its area?
(a) 300%
(b) 400%
(c) 600%
(d) 800%

Answer: D

Question. How many metres of carpet 50 cm wide will be required to cover the floor of a room 30 m × 20 m?
(a) 1000
(b) 600
(c) 2400
(d) 1200

Answer: D

Question. Three cubes whose edges are 3 cm, 4 cm and 5 cm respectively are melted to fo a single cube. Find the surface area of the new cube.
(a) 210 cm²
(a) 213 cm²
(c) 224 cm²
(d) 216 cm²

Answer: D

Question. The radii of the two circular field is in the ratio 3 : 5. The area of the first field is what percent less than the area of the second?
(a) 50%
(b) 60%
(c) 40%
(d) 64%

Answer: D

Q 1 Find the volume of a cuboid whose length is 8 cm, breadth 6 cm and height 3.5 cm.

Q 2 Find the altitude of a trapezium, the sum of the lengths of whose bases is 6.5 cm and whose area is 26 cm².

Q 3 Find the height of a cuboid whose volume is 275 cm³ and base area is 25 cm².

Q 4 Find the area of a rhombus whose diagonals are of measurements 6 cm and 8 cm.

Q 5 Find the volume of the cylinder whose base diameter is 14 cm and height is 10 cm.

Q 6 Find the area of a triangle whose base is 4 cm and altitude is 6 cm.

Q 7 Find the total surface area of a cube whose volume is 343 cm³.

Q 8 Find the side of a cube whose surface area is 2400 cm².

Q 9 How many bricks will be required for a wall which is 8 m long, 6m high and 22.5 cm thick, if each brick measures 25 cm X 11.25 cm X 6 cm?

Q 10 The diameter of garden roller is 1.4 m and it is 2 m long. How much area will it cover in 5 revolutions?

Q 11 Find the volume of a cuboid whose length is 8 cm, width is 3 cm and height is 5 cm.

Q 12 A cylindrical tank has a capacity of 5632 m3. If the diameter of its base is 16 m, find its depth.

Q 13 Find the volume of 64 cubes whose one side is 4 cm.

Q 14 Find the volume of a cylinder whose base radius is 14 cm and height is 35 cm.