Question

Find the area of four walls of a room of 7.5 m long, 4.5 m broad and 3 m high. Also,
the cost of plastering its floor, ceiling and four walls at the rate of 12 per square
neglecting the areas of doors and windows​

Answer 1

The area of four walls of a room is 72 square meters.

The cost of plastering its floor, ceiling and four walls at the rate of 12 per square = Rs 1674

Explanation:

Given : Length of room = 7.5 m

breadth =4.5 m

Height =3 m

Let length = l , breadth = b and height = h

Area of four walls = lateral surface area =2h (l+b)

= 2 (3)(7.5+4.5)=6(12)=72 square meters.

Hence, the area of four walls of a room is 72 square meters.

Total area of room : 2(lb+bh+hl) = 2((7.5)(4.5)+(4.5)(3)+(3)(7.5))

=2(69.75)=139.5 square meters.

Rate of plastering = Rs 12 per square

Then the total cost of plastering = (Rate of plastering)x (Total area of room)

= 12 x 139.5 =Rs 1674

Hence, the cost of plastering its floor, ceiling and four walls at the rate of 12 per square = Rs 1674

# Learn more :

The sum of the area of floor and ceiling of a room is equal to the area of four walls. If the room is 24m long and 16m wide, find the height of the room

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