The circumference of a circular pool is 157 meters, how many square meters does this pool occupy?
一个圆形水池的周长是157米，这个水池占地多少平方米？
<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>