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16 votes
16 votes
Find the area of the regular pentagon?

4.1cm and 6cm
Round your answer to the nearest tenth.

Find the area of the regular pentagon? 4.1cm and 6cm Round your answer to the nearest-example-1
User ThiagoLeal
by
3.2k points

1 Answer

30 votes
30 votes

Answer:

61.5 cm²

Explanation:

You want the area of a regular pentagon with side length 6 cm and apothem 4.1 cm.

Area

The area formula is ...

A = 1/2Pa

where P is the perimeter and 'a' is the apothem. Using the given values, we find the area to be ...

A = 1/2(5·6 cm)·(4.1 cm) = 61.5 cm²

The area of the pentagon is about 61.5 cm².

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Additional comment

A better approximation of the length of the apothem is 4.12915 cm. Using that value, the area rounds to 61.9 cm².

It always presents a problem when dimensions are given to 1 or 2 significant figures, and an answer is required that has more significant figures.

Apothem length and side length of a regular n-gon are rarely specified so each is consistent with the other. One or the other is sufficient to define the size of the n-gon.

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User Rich Ross
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3.3k points