What is the largest circle to be cut out of a square of paper with a circumference of 100 cm?
在一张周长为100厘米的正方形纸上要剪下一个最大的圆，这个圆的面积是多少？
<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">25 / 2</gadget>
<output>25/2 = around 12.5</output>

<gadget id="calculator">(25/2) ** 2</gadget>
<output>625/4 = around 156.25</output>

<gadget id="calculator">3.14 * (625/4)</gadget>
<output>490.625</output>

<result>490.625</result>