Cut the largest circle out of a square of cardboard with a circumference of 24 cm. What is the radius of this circle?
在一张周长为24厘米的正方形硬纸板上，剪一个最大的圆，这个圆的半径是多少？
<gadget id="calculator">24 / 4 / 2</gadget>
<output>3</output>

<result>3</result>