Cut a 4-meter-long log into three small columns and increase its surface area by 8 square decimeters______ Cubic decimeter

Cut a 4-meter-long log into three small columns and increase its surface area by 8 square decimeters______ Cubic decimeter

The area of the bottom surface of four cylinders is increased after the average section is three, so the area of the bottom of the cylinder is: 8 △ 4 = 2 (square decimeter), 4 M = 40 decimeter. From v = sh, we can get: 2 × 40 = 80 (cubic decimeter). Answer: the original volume of this wood is 80 cubic decimeter. So the answer is: 80

Cut a 4-meter-long log into three small sections, and increase the surface area by 12 square decimeters. The original volume of this log is () cubic decimeters
A、8
B、80
C、120
D、12

Cut it into 3 sections and saw it twice, adding 4 surfaces, 12 △ 4 = 3 square decimeters
4m = 40m
3 × 40 = 120 cubic decimeter
Choose C

Cut a 5-meter-long log into three small sections. The surface area is increased by 8 square decimeters. The volume of this log is () cubic decimeters
A. 10B. 40C. 100D. 200

5 m = 50 decimeter, 8 △ 4 × 50 = 2 × 50, = 100 (cubic decimeter)