1. Cut a 4-meter-long log into three small cylinders to increase the surface area by 8 square decimeters. The volume of this log is () cubic decimeter. Solution: After evenly cutting into three sections, increase the area of the bottom surface of four cylinders.

So the bottom area of the cylinder is 8÷4=2 (square decimeter),

4 meters =40 decimeters,

It can be obtained from V=Sh: 2×40=80 (cubic decimeter).

A: It turns out that the volume of this piece of wood is 80 cubic decimeters.

2. Xiao Ming used a piece of plasticine with a volume of 2 16 cubic centimeter to shape a cylinder and cone with equal bottom and equal height. The volume of a cylinder is () cubic centimeters larger than that of a cone.

Solution: The volume of the cone is 2 16÷4=54 (cubic centimeter).

The volume of the cylinder is 54×3= 162 (cubic centimeter);

162-54= 108 (cubic centimeter),

A: The volume of a cylinder is larger than that of a cone 108 cubic centimeter.