Answer:
1440 ft²
Explanation:
The roof is made up of 4 congruent triangles.
We first solve for the area of one of the triangles using the formula:
A = (1/2) · b · h
↓ plugging in given values
A = (1/2) · 40 ft · 18 ft
A = 20 ft · 18 ft
A = 360 ft²
Now, we can solve for the surface area of the entire roof by multiplying the area of one of the triangles by 4 (because there are 4 congruent triangles).
SA = 360 ft² · 4 = 1440 ft²
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Note that we can solve for the area of the triangles using the formula {A = (1/2) · b · h} because the slant height of a pyramid is perpendicular to the side of the pyramid's base that it connects to, thereby making it the height of the triangle that is the pyramid's side.
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