Draw a square as large as possible inside the circle. Given that the area of this square is 20 square centimeters, what is the area of the circle?
在圆内画一个尽可能大的正方形，已知这个正方形的面积是20平方厘米，求圆的面积是多少？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">3.14 * 10</gadget>
<output>31.4</output>

<result>31.4</result>