On a piece of rectangular paper with a length of 10 cm and a width of 8 cm, draw the largest circle. What is the radius of this circle in cm?
在一张长10厘米、宽8厘米的长方形纸上，画个最大的圆，这个圆的半径是多少厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<result>4</result>