Draw the largest circle on a square paper with a side length of 10 cm. What is the area of the circle in square centimeters?
在边长是10厘米的正方形纸上画一个最大的圆，圆的面积是多少平方厘米．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>