Cut a cylindrical wood billet with a base diameter of 6 decimeters and a height of 20 decimeters into a cuboid with a square base and constant height. What is the largest cubic decimeter of the volume of this cuboid?
将一个底面直径为6分米、高20分米的圆柱形木坯，削成一个底面是正方形、高不变的长方体木料．这个长方体的体积最大是多少立方分米？
<result>369</result>