Xiao Ming has a protractor (that is, a semicircle) with a diameter of 6 cm. What is its area in square centimeters?
小明有一个直径为6厘米的量角器(即半圆)，它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>