A square, with perimeter 20, is inscribed in a circle. What is the area of the circle?
Choices:  A) 8π  B) 11π  C) 10π  D) 12π  E) 12.5π
Area of circuscribed circle = pi/2*area of square   Area of square = (20/4)^2 = 5^2= 25   Area of circle = pi/2*4=12.5pi   Answer 12.5π
<result>E</result>
A square, with perimeter 20, is inscribed in a circle. What is the area of the circle?