Answer:
rA/2 = V
Step-by-step explanation:
Let's ignore the ends.
If the cylinder has radius r and height h, then the surface area is A = 2πrh. The 2πr factor is the circumference of the cylinder. For later use, let's solve this for πrh: πrh = A/2.
The volume of the cylinder is V = πr²h, where πr² is the area of the base.
This V = πr²h can be factored so that one of the factors is the area A of the sides of the cylinder: V = πr²h = r*πrh = r*(A/2) = rA/2 = V
