Draw two largest circles on a rectangular piece of paper with a width of 8 cm and a length of 12 cm. What is the area of a circle?
在宽8厘米，长12厘米的长方形纸上画两个最大的圆，一个圆的面积是多少．
<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>