Draw the largest semicircle in a rectangle with a length of 6 cm and a width of 4 cm. What is the area of the semicircle in square centimeters?
在长6厘米，宽4厘米的长方形中画最大的半圆，半圆的面积是多少平方厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">3.14 * (9/2)</gadget>
<output>14.13</output>

<result>14.13</result>