Geometry

Surface Area of a Cylinder

Cylinder Surface Area Formula

The formula for surface area of a cylinder is given as:
SA = 2πrh + 2πr2
Where SA is the surface area, r is the radius of the base circle, and h is the height of the cylinder.

surface area of a cylinder

Example Problems

Problem 1:
What is the surface area of a cylinder with a diameter of 20 and a height of 20?
Solution:
1.) Let’s convert diameter to radius. D = 2r, 20 = 2r, so r = 10.
2.) Now let’s plug the radius and height into the surface area formula.
SA = 2πrh + 2πr2
SA = 2π(10)(20) + 2π(102) = 2π(200) + 2π(100)
SA = 1,884.956
4.) The surface area is 1,884.956.

Problem 2:
A cylinder is measured to have a surface area of 24 square meters. It’s height and radius are equal. What is the height of the cylinder?
Solution:
1.) Let’s set up relations between height and radius that we can substitute into the formula.
h = r
rh = h2
r2 = h2
2.) Now let’s plug what we know into the surface area formula and solve for h.
SA = 2πrh + 2πr2
24 = 2πh2 + 2πh2
24 = 4πh2
1.910 = h2
h = 1.382
3.) The height of the cylinder is 1.382 meters.

Result :

Worksheet 1

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Cheat sheet

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