Cut out the largest circle on a piece of rectangular paper with a length of 15 cm and a width of 9 cm. What is the circumference of this circle in cm?
在一张长15厘米，宽9厘米的长方形纸上剪下一个最大的圆，这个圆的周长是多少厘米．
<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>