Draw the largest semicircle in a rectangle with a length of 10 cm and a width of 6 cm. What is the area of this semicircle in square centimeters?
在一个长10厘米宽6厘米的长方形里画一个最大的半圆，这个半圆的面积是多少平方厘米．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">25 / 2</gadget>
<output>25/2 = around 12.5</output>

<gadget id="calculator">3.14 * (25/2)</gadget>
<output>39.25</output>

<result>39.25</result>