The height of a cylinder is equal to the circumference of its bottom. If the height is shortened by 2 cm, the surface area will be reduced by 12 square cm. What is the side area of the cylinder Square centimeter

The height of a cylinder is equal to the circumference of its bottom. If the height is shortened by 2 cm, the surface area will be reduced by 12 square cm. What is the side area of the cylinder Square centimeter

36 square centimeters
The height h = the circumference of the bottom 2 π R, the height is reduced by 2 cm, the reduced part only has the area of the side of the cylinder, and the two bottoms are unchanged. We know that the side area of the cylinder is a rectangle, so the reduced part of 12 square cm is a rectangle with the circumference of the bottom 2 π R and the width of 2 cm, 2 π R * 2 = 12, r = 3 / π, H = 6, and the side area 2 π R * H = 36 square cm

The height of a cylinder is equal to the circumference of its bottom. If the height is shortened by 3 cm, the surface area will be reduced by 94.2 square cm. Find the side area of the cylinder

3 * 2 π r = 94.2 r = 5cm
H = 2 π r = 31.4cm
Area = 2 * π r square + 31.4 * 2 π r =?
The result is calculated by yourself

A cylindrical wood, cut along the diameter, the section is a square, the circumference of the bottom of the cylinder is 12.56 decimeters, calculate the volume of the cylinder

If the ground perimeter of the cylinder is 12.56dm, the diameter of the cylinder is 4dm
Because it is cut along the diameter and the section is a square, the height of the cylinder H = 4dm
So volume v = 3.14 * (4 / 2) ^ 2 * 4 = 50.24dm ^ 3