Question

The perimeter of the floor of a room is 140. The height of the room is 4.Find the area of its four walls.(lateral surface area)​

Answer 1

Given :

The perimeter of the floor of a room is 140. The height of the room is 4.

To find :

Find the area of its four walls.(lateral surface area)

Solution :

Perimeter of Rectangle = 2 (L + B)

Height = 4 m.

Area of walls = 2h (L+ B)

= h 2(L + B)

= 4 × 140

= 560m²

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More Formulas :

Area of Rectangle = L × B

Area of Square = (Side)²

Perimeter of Square = 4a

Perimeter of Rectangle = 2 (L + B )

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Answer 2

$\huge \sf \color{magenta}{\underline{\underline{Answer}}}:$
$\large {\sf Area \: of \: walls \: = \: 560m²}$
$\\ \huge \sf \color{magenta}{\underline{\underline{Solution}}}:$

$\\ \large \sf \color{green}{\underline{Given}}:$
➽ The perimeter of the floor of a room, 2(l+b)= 140
➽ Height of the room,h = 4
$\\ \large \sf \color{green}{\underline{To \: find }}:$
➽ Area of walls
$\\ \large \tt \color{green}{\underline{we \: know \: that , }}:$
✯ Perimeter of Rectangle(room) = 2(l+b)
✯ Area of walls = 2h(l+b)

so,
Area of walls = 2h(l+b)
$\: \: \: \: \: \: \: \sf = h[2(l+b)] \\ \sf \: \: \: \: \: \: \: = 4× 140 \: \: \: (Given) \\ \: \: \: \: \: \: \: ➩ \boxed{\tt 560m²}$

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$\large {\sf Area \: of \: walls \: = \: 560m²}$
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