2020 · Q79
If the perimeter of a circle and a square are equal, then what is the ratio of the area of the circle to that of the square?
Elementary MathematicsCircles
- A1:π
- B2:π
- C3:π
- D4:π
Explanation
2*pi*r = 4a gives a = pi*r/2; the area ratio is pi*r^2/(pi^2*r^2/4) = 4/pi. Hence option (D). With r = 2: circle area 4*pi and square side pi, giving 4*pi/pi^2 = 4/pi.