square cardboard with a circumference of 12 cm is cut into the largest circle, what is the area of this circle in square centimeters?
一张正方形纸板，周长是12厘米，把它剪成一个最大的圆，这个圆的面积是多少平方厘米？
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) ** 2</gadget>
<output>9/4 = around 2.25</output>

<gadget id="calculator">3.14 * (9/4)</gadget>
<output>7.065</output>

<result>7.065</result>