Draw a circle as large as possible on a piece of rectangular paper with a length of 9 cm and a width of 6 cm. The distance between the two compasses cannot exceed how many centimeters.
在一张长9厘米、宽6厘米的长方形纸上画一个尽可能大的圆，则圆规两间的距离不能超过多少厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<result>3</result>