If a square with a side length of 5 cm is cut into the largest circle, by what percentage is the area reduced?
把一个边长5厘米的正方形剪成一个最大的圆，面积减少了百分之几？
<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) ** 2</gadget>
<output>25/4 = around 6.25</output>

<gadget id="calculator">3.14 * (25/4)</gadget>
<output>19.625</output>

<gadget id="calculator">25 - 19.625</gadget>
<output>5.375</output>

<gadget id="calculator">5.375 / 25</gadget>
<output>0.215</output>

<result>0.215</result>