S.chand publication solution of class 6 chapter 25 exercise 25 A

EXERCISE 25 A

1. Find the surface area of each of the cuboids whose dimensions are given below

 (i) (ii) (iii) (iv) (v) l 9 cm 5 cm 12 cm 5 cm \$5\dfrac{1}{2}\$ b 4 cm 5 cm 10 cm 1.5 cm 4cm h 3 cm 10 cm 4 cm 2.4 cm \$10\dfrac{1}{2}\$

2. Find the surface area of the following cubes.

(i) l = 8 cm

(ii) l = 12 cm

(iii) \$l=\dfrac{1}{2}~m\$

(iv) l = 5 dm

3. The total surface area of cube is 96 cm2 . what is the length of its sides ?

4. The total surface of a wooden box which is in the shape of a cube . If the edge of the box is 25 cm.

5. Find the cost of painting all round the outer surface of a box with lid 100 cm long , 80 cm wide and 60 cm high at 2 rupees per 40 cm2

6. The dimensions of an oil can are 26 cm × 26 cm × 45 cm . Find the area of the tin sheet required for making 20 such cans . If 1 sq m of the tin sheet costs 10 rupees , find the cost of tin used for these 20 cans .

7. Find the area of the four walls with following measurements

(i) Length = 8 m , width = 6 m and height = 4 cm

(ii) Length = 10 m , width = 7 m and height = 5 m

8. (i) A rectangular room is 6 m long, 5 m wide and 4 m high. Find the total surface area of the four walls .

(ii) If the windows and door in the above room are made up of 20% of the wall area , how much paint will be needed to give the four walls (excluding the windows and door) two coats of paint if a litre of paint is used to cover 18 m2 in one coat .

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