The area of a sector is (1/3) the area of a circle equal to its radius. What is the central angle of this sector.
一个扇形的面积是一个与它的半径相等的圆面积的(1/3)，这个扇形的圆心角是多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">360 * (1/3)</gadget>
<output>120</output>

<result>120</result>