A sector and a circle have the same radius and their area ratio is 2:5 What is the central angle of the sector.
一个扇形和一个圆的半径相等，它们的面积比是2：5这个扇形圆心角是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">360 * (2/5)</gadget>
<output>144</output>

<result>144</result>