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प्रश्न
The perimeter of a floor of a room is 30 m and its height is 3 m. Find the area of four walls of the room.
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उत्तर
\[\text { Perimeter of the floor of the room = 30 m } \]
\[\text { Height of the oom = 3 m } \]
\[\text { Perimeter of a rectangle = 2 } \times { \text { (length + breadth) }} = 30 m \]
\[\text { So, area of the four walls = 2} \times \text { (length }\times\text { height + breadth }\times \text { height) }\]
\[ = 2 \times \text { (length + breadth) } \times \text { heigh }t\]
\[ = 30 \times 3 = 90 m^2\]
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