What is the area in square centimeters of a sector with a central angle of 120° and a radius of 3 centimeters?
一个圆心角是120°，半径为3厘米的扇形面积是多少平方厘米．
<gadget id="calculator">120 / 360</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(1/3) * 3.14 * 9</gadget>
<output>9.42</output>

<result>9.42</result>