The diameter of the bottom surface of a cylindrical part is 8 cm. There is a cylindrical straight hole at one end of the part. The diameter of the round hole is 6 cm and the depth of the hole is 7 cm. If the part of the part that is in contact with air is coated with antirust paint, how many square centimeters should it be coated? It's not 12 meters. It's 12 centimeters

The diameter of the bottom surface of a cylindrical part is 8 cm. There is a cylindrical straight hole at one end of the part. The diameter of the round hole is 6 cm and the depth of the hole is 7 cm. If the part of the part that is in contact with air is coated with antirust paint, how many square centimeters should it be coated? It's not 12 meters. It's 12 centimeters

Area of both ends 4 * 4 * π + 4 * 4 * π - 3 * 3 * π
Pore area 6 * π * 7 + 3 * 3 * π
Side area 4 * 4 * π * 1200
The total area is (16 + 16-9 + 42 + 9 + 16 * 1200) π = 60551 square centimeters

A cylinder, its bottom diameter and height are 10 decimeters, its side area is______ Square decimeter

14 × 10 × 10 = 3.14 × 100 = 314 (square decimeter). Answer: its side area is 314 square decimeter

A cylinder casting, bottom circumference 12.56 decimeters, cut it into a largest cone casting, cut the volume

12.56÷3.14÷2＝2
2 × 2 × 3.14 × 3 × (1-1 / 3) = 25.12 cubic decimeter