regular pentagon

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 :)

Here is a way to solve: