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# regular pentagon

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Find the area of a regular pentagon with a side of 5cm round to nearest tenth

Mar 6, 2021

#1
+197
+3

Hey there!

The formula for the area of a pentagon is as follows:

$$Area=\frac{1}{4}\sqrt{5(5+2\sqrt{5})}*a^2$$

Since all sides are equal to 5cm, just sub this into "a" to get the area:

$$Area=\frac{1}{4}\sqrt{5(5+2\sqrt{5})}*5^2\approx43.01194cm^2$$

You want the nearest tenth so your answer will be: $$43.0cm^2$$

Hope this helped :)

Mar 7, 2021
#2
+31212
+1

Here is a way to solve:

Mar 7, 2021