What is the area of a circular pot with a diameter of 20 cm?
一个圆形锅盖的直径为20厘米，它的面积是多少．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<result>314</result>