Question

The area of four walls of a room is 168 m square .the breadth and height of the room are 10 m and 4 m respectively. find the length of the room.

Answer 1

It is given that area of four walls of a room is 168 m², and breadth and height of the room are 10 m and 4 m respectively.


Area of four walls = 168 m²
Height of the room = 4 m
Breadth of the room = 10 m


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From the properties of cuboid, we know
Area of four walls = 2( length + breadth ) x height
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Therefore,

= > 168 m² = 2( length + 10 m ) x 4 m

= > 168 m² / ( 2 x 4 m ) = Length + 10 m

= > 21 m = length + 10m

= > 21m - 10 m = length

= > 11m = length


Hence,
Length of the room is 11 m
$\:$

Answer 2

Answer:

11 m

Step-by-step explanation:

Area of the 4 walls =  168 m²

Breadth = 10 m

Height = 4 m

Find the length:

Area of the 4 walls = Perimeter of the floor x height

Area of the 4 walls = 2(Length + breadth) x height

168 = 2(Length + 10) x 4

168 = 8(Length + 10)

Length + 10 = 21

Length = 21 - 10 = 11 m

Answer: The length is 11m