If the area of a square is 40 square centimeters, what is the area of its circumscribed circle?
正方形的面积是40平方厘米，则它的外接圆的面积是多少．
<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">3.14 * 20</gadget>
<output>62.8</output>

<result>62.8</result>