If the ratio of the radii of the two circles is 3:4, what is the ratio of the areas of the two circles?
两圆的半径之比是3：4，那么这两圆面积的比值是多少．
<gadget id="calculator">9 / 16</gadget>
<output>9/16 = around 0.5625</output>

<result>9/16 = around 0.5625</result>