There are two circles A and B. The radius of circle A is 80% of the radius of circle B. It is known that the circumference of circle B is 31.4 cm. How much is the area of circle A less than that of circle B?
有A、B两个圆，A圆半径是B圆半径的80%，已知B圆的周长是31.4厘米，则A圆面积比B圆面积少多少．
<gadget id="calculator">32 / 100</gadget>
<output>8/25 = around 0.32</output>

<result>8/25 = around 0.32</result>