If the radius of a circle is shortened to (1/3) of its original length, then the area is reduced to its original size.
一个圆的半径缩短为原来长度的(1/3)，那么面积缩小为原来的多少．
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<result>1/9 = around 0.111111</result>