<PRE><B>Question 260303</B>
The perimeter of a semi-circle is pi*d/2 + d
The perimeter has 2 parts: the circular part which is 1/2 the circumference of a circle and a flat part which is the diameter of the circle.
pi*d/2 + d=20
pi*d+2d=40
d(pi+2)=40
d=40/(pi+2)
r=20/(pi+2)
.
A=(pi*r^2)/2
=pi*(20/(pi+2))^2/2
=pi*(400/(pi+2)^2)*1/2
=200pi/(pi+2)^2 or 23.77
.
Ed</PRE>