Draw the largest semicircle in a rectangle with a length of 8 decimeters and a width of 6 decimeters. What is the area of the semicircle?
在长8分米宽6分米的长方形中画一个最大的半圆，半圆的面积是多少？
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>