If the perimeter of a semicircle is 15.42 cm, what is its area in square centimeters?
一个半圆形的周长是15.42厘米，它的面积是多少平方厘米．
<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>