Draw the largest circle in a square whose side length is 8 cm. What is the radius of this circle in cm?
在一个边长是8厘米的正方形里面画一个最大的圆，这个圆的半径是多少厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<result>4</result>