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3. Assertion (A): The volume of a cuboid of length 6 cm, breadth 5 cm and height 10 cm is 150 cm .
Reason (R): The volume of cuboid is the product of length, breadth, and height.
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4. Assertion (A): The area of a rhombus is 48 cm . One diagonal is 8 cm. The other diagonal is 12 cm.
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Reason (R): Area of a rhombus = × d × d , where d and d are diagonals of a rhombus.
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C. Fill in the blanks.
1. The surface area of a cuboid formed by joining two cubes of side ‘a’ face to face is .................. .
2. .................. of a solid is the measurement of the space occupied by it.
3. .................. surface area of a room = Area of 4 walls.
4. Two cylinders of same volume have their radii in the ratio 1 : 6, then ratio of their heights is ........... .
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5. The area of a parallelogram is 60 cm and one of its altitudes is 5 cm. The length of its corresponding
side is .................. .

D. State whether the following statements are true (t) or false (F).
1. Two cuboids with equal volumes will always have equal surface areas.
2. The area of a trapezium becomes 4 times if its height gets doubled.

3. The areas of two opposite faces of a cuboid are equal.
4. Two cylinders with equal volume will always have equal surface areas.

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5. 1L = 1000 cm .
6. The ratio of the area of a circle to the area of a square whose side is equal to radius of the circle is
p : 1.
E. Answer the following.

1. From a circular sheet of radius 5 cm, a smaller circular sheet of radius 2 cm is cut out. Calculate the
area of the remaining sheet.
2. The circumference of the front wheel of a cart is 3 m long, and that of the back wheel is 4 m long.
What is the distance travelled by the cart, when the front wheel makes five more revolutions than
the rear wheel?
3. Most of the sailboats have two sails, the jib and the mainsail. Assume that the sails are triangles.
Find the total area of each sail of the sailboats to the nearest tenth. (up to 2 decimal places)
16.8 m
(a) (b) (c)
8.9 m 25 m 16.8 m

22 m
19.5 m 23.9 m 12.4 m
22.3 m 20 m 9.6 m

10.9 m 8.6 m
3 m

4. A river 2 m deep and 45 m wide is flowing at the rate of 3 km per hour. Find the amount of water
in cubic metres that runs into the sea per minute.

5. How many bricks, each 25 cm by 15 cm by 8 cm, are required for building a wall 32 m long, 3 m
high and 40 cm thick?

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