Divide the circle into several equal parts, cut them and assemble them into an approximate rectangle. The circumference of the rectangle is 4 cm longer than the circumference of the circle. What is the radius of the circle in cm?
把圆分成若干等份，剪开后拼成一个近似的长方形，长方形的周长比圆的周长多4厘米，圆的半径是多少厘米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<result>2</result>