Draw the largest square in a circle with a circumference of 6.28 cm. What is the area of this square?
在一个周长6.28cm的圆内画一个最大的正方形，这个正方形的面积是多少．
<gadget id="calculator">6.28 / 3.14 / 2</gadget>
<output>1</output>

<gadget id="calculator">6.28 / 3.14 / 2 / 2</gadget>
<output>0.5</output>

<gadget id="calculator">1 * 0.5 * 4</gadget>
<output>2</output>

<result>2</result>