If a 2-meter-long cylindrical steel is worn into four small columns, the surface area and volume of the cylinder will increase by 56.52 square centimeters compared with the original cylinder steel volume by 10 minutes

If a 2-meter-long cylindrical steel is worn into four small columns, the surface area and volume of the cylinder will increase by 56.52 square centimeters compared with the original cylinder steel volume by 10 minutes

Because it is cut into four small cylinders, the circle area increases by six, so 56.52/6 = 9.42 square centimeter,
Therefore, the total volume: 200x9.42 = 1884 cm3

A 3 meter long round steel is cut into three sections, and the surface area is increased by 12.56 square decimeters

3 M = 30 decimeter, 12.56 △ 4 × 30 = 3.14 × 30 = 94.2 (cubic decimeter); answer: the volume of round steel is 94.2 cubic decimeter

A 3-meter-long round steel is cut into three sections along the direction parallel to the cross section, and the surface area is increased by 12.56 square decimeters?

The surface area increased by (3-1) × 2 = 4 sections
3 meters = 30 decimeters
Sectional area = 12.56 △ 4 = 3.14 (square decimeter)
Original volume = 3.14 × 30 = 94.2 (cubic decimeter)