What is the area of a semicircle whose radius is 10 cm?
一个半圆的半径是10厘米，它的面积是多少．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">3.14 * 50</gadget>
<output>157</output>

<result>157</result>