Divide a circle into several equal parts along its radius, and then assemble it into an approximate rectangle. Then the perimeter of the rectangle is 6 cm longer than the perimeter of the circle. What is the radius of the circle in centimeters?
把一个圆沿它半径平均分成若干份，然后把它拼成一个近似长方形，则这个长方形的周长比圆的周长增加了6厘米，这个圆的半径是多少厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<result>3</result>