There is a circle with the same area as a rectangle, the circumference of the circle is 12.56cm, the length of the rectangle is 4cm, and the width in cm.
有一个圆与一个长方形的面积相等，圆的周长是12.56cm，长方形的长是4cm，宽是多少cm．
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<result>3.14</result>