+0  
 
0
111
1
avatar

What is the area of a regular pentagon with a 12-cm radius?

 Jun 10, 2022
 #1
avatar+124676 
+1

The pentagon will be composed of 5 congruent isosceles triangles

 

Their equal sides  = 12   and  the  included angle between  these sides =  72°

 

The  area of one of these =   (1/2) (12^2) sin (72°)  =   72sin 72°

 

So the area is ....5  (72)sin (72°)  =   360 sin (72°)   ≈    342.38   cm^2

 

 

cool cool cool

 Jun 10, 2022

25 Online Users

avatar
avatar