If the circumference of a circle is 1.57 meters, what is its area in square meters?
一个圆的周长是1.57米，它的面积是多少平方米．
<gadget id="calculator">1.57 / 3.14 / 2</gadget>
<output>0.25</output>

<gadget id="calculator">0.25 ** 2</gadget>
<output>0.0625</output>

<gadget id="calculator">3.14 * 0.0625</gadget>
<output>0.19625</output>

<result>0.19625</result>