Answer:
80 in²
Explanation:
When side length and apothem of a regular polygon are given, the applicable area formula is ...
A = 1/2Pa
where P is the perimeter of the polygon, and 'a' is its apothem.
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The perimeter of a regular 8-sided polygon will be 8 times the side length, so the area is ...
A = 1/2(8×4 in)(5 in) = 80 in²