If the circumference of a semicircle is 514 cm, what is its area in square centimeters?
一个半圆的周长是514厘米，则它的面积为多少平方厘米．
<gadget id="calculator">100 ** 2</gadget>
<output>10_000</output>

<gadget id="calculator">10_000 / 2</gadget>
<output>5_000</output>

<gadget id="calculator">3.14 * 5_000</gadget>
<output>15_700</output>

<result>15_700</result>