A rectangular cardboard is 12 cm long and 8 cm wide. Cut a largest circle out of this rectangular cardboard. What is the radius of this circle in cm?
一张长方形纸板长12厘米，宽8厘米，在这张长方形纸板中剪一个最大的圆，这个圆的半径是多少厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<result>4</result>