The circumference of a semicircle is 15.42CM, what is the area of this semicircle?
一个半圆的周长为15.42CM，这个半圆的面积为多少．
<gadget id="calculator">15.42 / 5.14</gadget>
<output>3</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">3.14 * 3 * (3/2)</gadget>
<output>14.13</output>

<result>14.13</result>