To calculate the are of the sides of a cylinder, you take the circumference of the base, or circle, and multiply it times the height. To calculate the circumference of a circle we use the formula 2*pi*r, or 15pi. We multiply this times 20 to get 300pi cm. If you are using 3.14 for pi, this is 942, or if you are using actual pi, around 942.4777.
