the straight line where one side of the rectangle is located is the rotation axis, and the rotating body formed by the surface formed by rotating 360° on the other three sides is called a circular cylinder. that is, one side of the ag rectangle is the axis, and the geometry obtained by rotating 360° is a cylinder. .

volume v = πr²h

side area l = 2πrh

bottom area t = b = πr²

surface area a = l + t + 2b = 2πrh + 2(πr²) = 2πr(h+r)