circle has the same area as a rectangle. The radius of the circle is equal to the width of the rectangle. The circumference of the circle is 20.15 cm. What is the length of the rectangle in cm?
一个圆与一个长方形的面积相等，圆的半径等于长方形的宽，圆的周长是20.15cm，长方形的长是多少cm．
<gadget id="calculator">20.15 / 2</gadget>
<output>10.075</output>

<result>10.075</result>