SOLUTION: http://i.imgur.com/GSOlmwX.jpg In the figure above, O and P are the center of two semicircles of radius r. If the length of the perimeter is 8π+16, what is the value of r?

Algebra ->  Expressions -> SOLUTION: http://i.imgur.com/GSOlmwX.jpg In the figure above, O and P are the center of two semicircles of radius r. If the length of the perimeter is 8π+16, what is the value of r?      Log On


   



Question 1043374: http://i.imgur.com/GSOlmwX.jpg
In the figure above, O and P are the center of two semicircles of radius r. If the length of the perimeter is 8π+16, what is the value of r?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The perimeter of a circle is 2*pi*r
The perimeter of a semicircle is pi*r
The perimeter of the semicircles, or the length of the line, is 2*pi*r=8*pi +16
Divide by 2 both sides
pi*r=4*pi+8
r=[(4*pi)+8]/pi
That is also 4+(8/pi)