A conical container with a height of 18 cm is filled with water, and all the water is poured into a cylindrical container with the same height as its bottom. What is the height of the water surface in cm?
高18厘米的圆锥形容器装满水，把这些水全部倒入与它等底等高的圆柱形容器中，水面高多少厘米．
<result>6</result>