How do you calculate the total area of a cylinder?

Answer 1

Calculate the circumference of the circle formed at the end of the cylinder (which is pi times the diameter) and multiply that by the height of the cylinder to get the surface area of the side of the cylinder. If you also want to add the surface area of the two circular ends of the cylinder, that is pi times the radius squared. Pi is approximately 3.14 which is accurate enough for most purposes (but many more digits are available if you need them). Let us imagine, then, that you have a cylinder that is 10" high, and 2" in diameter. The circumference of the end circles is then 6.28 and the side of the cylinder is 62.8 square inches. Each end circle has an area of 3.14 x one inch squared, which is 3.14 square inches. Two such circles are therefore 6.28 square inches (a tenth of the area of the side) and the total of the side and top and bottom of the cylinder is then 69.08 square inches.