A square has a side length of 6 cm. Draw two largest semicircles in this square. What is the area of a semicircle in square centimeters?
一个正方形，边长是6厘米，在这个正方形里画两个最大的半圆，一个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>