Draw the largest circle in a square with a side length of 10 meters. What is the area of this circle in square meters?
在一个边长为10米的正方形中画一个最大的圆，这个圆的面积是多少平方米．
<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>