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Question
A cloassroom is 11 m long, 8 m wide and 5 m high. Find the sum of the areas of its floor and the four walls (including doors, windows, etc.)
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Solution
\[\text { Lenght of the classroom = 11 m } \]
\[\text { Width = 8 m } \]
\[\text { Height = 5 m }\]
\[\text { We have to find the sum of the areas of its floor and the four walls (i . e . , like an open box) } \]
\[ \therefore \text { The sum of areas of the floor and the four walls = (length }\times\text { width) } + 2 \times\text { (width }\times \text { height + length } \times\text { height) }\]
\[ = (11 \times 8) + 2 \times (8 \times 5 + 11 \times 5)\]
\[ = 88 + 2 \times (40 + 55)\]
\[ = 88 + 190\]
\[ = 278 m^2\]
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