Answer:
The measure of the radius c is [tex]12.36\ cm[/tex]
Step-by-step explanation:
we know that
The central angle of a regular pentagon is equal to
[tex]\frac{360\°}{5}= 72\°[/tex]
In the right triangle of the figure
[tex]cos(72\°/2)=\frac{10}{c}[/tex]
[tex]c=\frac{10}{cos(36\°)}=12.36\ cm[/tex]
