If a carpet is laid on a staircase with a total length of 2.5m and a total height of 2m, what is the minimum length of the carpet in m?
在总长为2.5m，总高为2m的楼梯上铺设地毯，至少需要地毯的长度为多少m．
<gadget id="calculator">2.5 + 2</gadget>
<output>4.5</output>

<result>4.5</result>