Surface area of cylinder =2× bottom area+side area.
The side of a cylinder is square or rectangular after being unfolded along the height, and the length after being unfolded is the circumference of the bottom surface and the width is the height (it is square when the circumference of the bottom surface is equal to the height, so the special case when the side surface is unfolded along the height is square), so the lateral area = the circumference of the bottom surface × the height.
At the bottom of the cylinder are two completely equal circles.
The distance between the two bottom surfaces is called the height of the cylinder. A cylinder has countless heights, all of which are of equal length.
Finding the volume of a cylinder is the same as finding the volume of a cuboid or cube, and it is both the bottom area × the height: if the radius of the bottom surface of the cylinder is r and the height is h, then the volume V: V = π R2H.
If s is the bottom area, the height is h, and the volume is v: v = sh.