Cut the largest circle out of a piece of square paper with a side length of 6 decimeters. What is the area of the circle?
用一块边长6分米的正方形纸剪一个最大的圆，圆的面积是多少？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>