The radius of a circular piece of glass is 20 cm, what is the area in square centimeters?
一块圆形玻璃的半径是20厘米，面积是多少平方厘米？
<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<result>1_256</result>