If the h of the cylinder is shortened by 2cm, the surface area will be reduced by 12.56cm? h: High. V: volume

If the h of the cylinder is shortened by 2cm, the surface area will be reduced by 12.56cm? h: High. V: volume

Circumference of bottom circle = 12.56 / 2 = 6.28 (CM)
When expanded, it is a square, indicating that the perimeter of the bottom is equal to the height
Radius = 6.28 / 2 / 3.14 = 1 (CM) v = sh = 3.14 * 1 ^ 2 * 6.28 = 19.7192 (CC)

If a cuboid is increased by 2 cm in height, it will become a cube. At this time, the surface area will be increased by 56 square cm compared with that of the original cuboid

The original cuboid circumference is 56 / 2 = 28 cm
Length = width = 28 / 4 = 7 (CM);
Height 7-2 = 5 (CM)

When the side area of a cylinder is expanded, a square with side length of 12.56 cm is just obtained. The height of the cylinder is () cm

It's 12.56cm