The circumference ratio of circle A to circle B is 2:3, then the area of circle A is ((())/(())) of the area of circle B.
甲圆与乙圆的周长比是2：3，那么甲圆的面积是乙圆面积的((())/(()))．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>