The central angle of a sector is 18° and the radius is 10 cm. What is the area of the sector in square centimeters?
一个扇形的圆心角为18°，半径为10厘米，这个扇形的面积是多少平方厘米．
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 3.14 * 9</gadget>
<output>1.413</output>

<result>1.413</result>