The diameter of the circular flower bed in the middle of the road is 100 meters, what is the area of the flower bed in square meters?
马路中间圆形花坛的直径是100米，这个花坛的面积是多少平方米？
<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">50 ** 2</gadget>
<output>2_500</output>

<gadget id="calculator">3.14 * 2_500</gadget>
<output>7_850</output>

<result>7_850</result>