What is the area of a sector with a radius of 5 cm and a central angle of 60°?
半径是5厘米，圆心角是60°的扇形面积是多少平方厘米．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">60 / 360</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">3.14 * 25 * (1/6)</gadget>
<output>13.083333</output>

<result>13.083333</result>