Draw the largest circle in a square with an area of 12 square centimeters. What is the area of this circle?
在一个面积为12平方厘米的正方形内画一个最大的圆，这个圆的面积为多少．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 3</gadget>
<output>9.42</output>

<result>9.42</result>