Question

perimeter of the room is 40 m and its height is 4 metre find the area of the four walls​

Answer 1

Area of the four walls =2(l+b)h

Since we already know perimeter of rectangle=2(l+b)=40

Substitute this value

40xh

40x4=160m

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Answer 2

Answer:

See, you want the area of four Wales which means it the lateral surface area.

Now, the lateral surface area is found by the formula :- 2(l+b)h

ACQ. 2(l+b)= 40

H= 4

So lateral surface area = 40×4

= 160m^2