The radius of the bottom surface of a cylinder is 6 decimeters. If you saw it into 4 sections along the direction parallel to the bottom surface, how many square decimeters more than the original surface area

The radius of the bottom surface of a cylinder is 6 decimeters. If you saw it into 4 sections along the direction parallel to the bottom surface, how many square decimeters more than the original surface area

Shi Kaiyu,
Saw into 4 sections, bottom surface added:
(4-1) × 2 = 6
The bottom area is:
3.14 × 6 × 6 = 113.04 (square decimeter)
The surface area is increased compared with the original
113.04 × 6 = 678.24 (square decimeter)

A piece of wood with a square bottom is 8 decimeters high. After sawing the wood into two sections, the surface area increases by 1.28 square decimeters. What is the original surface area of the wood?

1.28 △ 2 = 0.64 square decimeter
0.64=0.8×0.8
So the side length of a square is 0.8 decimeter
Surface area = 0.8 × 8 × 4 + 1.28 = 26.88 square decimeter

If a cylinder is sawn into two sections along the cross section, the surface area increases by 6.28 square decimeters
If a cylinder is sawn into two sections along the cross section, the surface area will increase by 6.28 square decimeters. If the bottom area will increase by 8 square decimeters, what is the volume of the cylinder? What is the maximum volume of a cone made of this cylinder?
If a cylinder is sawn into two sections along the cross section, the surface area will increase by 6.28 square decimeters. If the diameter along the bottom surface is increased by 8 square decimeters, what is the volume of the cylinder cubic decimeters? What is the maximum volume of a cone made from this cylinder?

6.28 / 2 = 3.14 square decimeters (bottom area or cross-sectional area)
4m = 40m
3.14 * 40 = 125.6 cubic decimeter (volume)