Class 8th mensuration

 1. If the height of a cylinder becomes 1/4 of the original height and the radius is doubled, then which of the following will be true? 

(a) Volume of the cylinder will be doubled. 

(b) Volume of the cylinder will remain unchanged. 

(c) Volume of the cylinder will be halved. 

(d) Volume of the cylinder will be1/4 of the original volume 

2. The surface area of the three coterminous faces of a cuboid are 6, 15 and 10 cm2, respectively. The volume of the cuboid is

 (a) 30 cm3 (b) 40 cm3 (c) 20 cm3 (d) 35 cm3 

3. The volume of a cube is 64 cm3 . Its surface area is 

(a) 16 cm2 (b) 64 cm2 (c) 96 cm2 (d) 128 cm2 

4. What is the area of the rhombus ABCD below if AC = 6 cm, and BE = 4cm?

 (a) 36 cm2 (b) 16 cm2 (c) 24 cm2 (d) 13 cm2 

5. The perimeter of a trapezium is 52 cm, and its each non-parallel side is equal to 10 cm with a height 8 cm. Its area is 

(a) 124 cm2 (b) 118 cm2 (c) 128 cm2 (d) 112 cm2

 6. The volume of a cylinder whose radius r is equal to its height is 

(a) 1/4 πr3 (b) πr3 /32 (c) πr3 (d) πr3  

Mary wants to decorate her Christmas tree. She wants to place the tree on a wooden box covered with coloured paper with picture of Santa Claus on it (see the below figure). She must know the exact quantity of paper to buy for this purpose. The box has length, breadth and height as 80 cm, 40 cm and 20 cm respectively and she wants to use square sheets of paper of side 40 cm for the decoration.

 7. Find the total surface area of the box. 

(a) 11200 cm2 (b) 12000 cm2 (c) 12100 cm2 (d) none of these

 8. Find the area of each sheet of the paper. 

(a) 1600 cm2 (b) 1620 cm2 (c) 1610 cm2 (d) none of these

 9. Find the number of sheets required. 

(a) 6 (b) 8 (c) 7 (d) 9 

10. Find the volume of the box. 

(a) 640 cm3 (b) 6400 cm3 (c) 64000 cm3 (d) none of these

 11. Find the area of a rhombus whose side is 5 cm and whose altitude is 4.8 cm. If one of the diagonals is 8 cm long, find the length of the other diagonal. 

12.A carpenter makes a box which has a volume of 13,400 cm3 . The base has an area of 670 cm2 . What is the height of the box? 

13.A cuboidal tin box opened at the top has dimensions 20 cm × 16 cm × 14 cm. What is the total area of metal sheet required to make 10 such boxes?

14 .A suitcase with measures 80 cm x 48 cm x 24 cm is to be covered with a tarpaulin cloth. How many meters of tarpaulin of width 96 cm is required to cover 100 such suitcases? 

15.A company packages its milk powder in cylindrical container whose base has a diameter of 14 cm and height 20 cm. Company places a label around the surface of the container (as shown in figure). If the label is placed 2 cm from top and bottom, what is the area of the label?

16 .Length of the fence of a trapezium shaped field ABCD is 120 m. If BC = 48 m, CD = 17 m and AD = 40 m, find the area of this field. Side AB is perpendicular to the parallel sides AD and BC. 

17.A milk tank is in the form of cylinder whose radius is 1.5 m and length is 7 m. Find the quantity of milk in liters that can be stored in the tank. 

 18.Water is pouring into a cuboidal reservoir at the rate of 60 liters per minute. If the volume of reservoir is 108 m^3, find the number of hours it will take to fill the reservoir.

 19 .Diameter of cylinder A is 7 cm and the height is 14 cm. Diameter of cylinder B is 14 cm and height is 7 cm. Without doing any calculations can you suggest whose volume is greater? Verify it by finding the volume of both the cylinders. Check whether the cylinder with greater volume also has greater surface area. 

20 .Diagram of the adjacent picture frame has outer dimensions = 24 cm × 28 cm and inner dimensions 16 cm × 20 cm. Find the area of each section of the frame, if the width of each section is same.