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Geometry
Surface Area of Cylinders
By Mr. Wall
Surface Area
Cylinder – (circular prism) a prism with two parallel, equal circles on opposite sides.
To find the surface area of a cylinder we can add up the areas of the separate faces.
Surface Area
In a cylinder there are a pair of opposite and equal circles.
We can find the surface area of a cylinder by adding the areas of the two blue ends (A) and the yellow sides (B).
B
A
Surface Area
We can find the area of the two ends (A) by using the formula for the area of a circle.
A = π r2
Side Area Number of
Sides
Total Area
A
B
Total
B
A5cm
8cm
Surface Area
We can find the area of the two ends (A) by using the formula for the area of a circle.
A = π r2
Side Area Number of Sides
Total Area
A 78.5 cm2
2 157 cm2
B
Total
B
A5cm
8cm
Surface Area
If we “unwrapped” the cylinder, what shape would the outside “B” be?
Side Area Number of Sides
Total Area
A 78.5 cm2
2 157 cm2
B
Total
B
A5cm
8cm
Surface Area
“B” would be in the shape of a rectangle, with the height forming one side and the circumference of the top forming the second side.
Side Area Number of Sides
Total Area
A 78.5 cm2
2 157 cm2
B
Total
B
A5cm
8cm
Surface Area
A = b * h
A = 2πr * h
Side Area Number of Sides
Total Area
A 78.5 cm2
2 157 cm2
B
Total
B
A5cm
8cm
Surface Area
A = 2πr * hA = 2 (3.14) (5) * 8
Side Area Number of Sides
Total Area
A 78.5 cm2
2 157 cm2
B
Total
B
A5cm
8cm
Surface Area
A = 2πr * hA = 251.2 cm2
Side Area Number of Sides
Total Area
A 78.5 cm2 2 157 cm2
B 251.2 cm2
1 251.2 cm2
Total
B
A5cm
8cm
Surface Area
A = 2πr * hA = 251.2 cm2
Side Area Number of Sides
Total Area
A 78.5 cm2 2 157 cm2
B 251.2 cm2
1 251.2 cm2
Total 408.2 cm2
B
A5cm
8cm
Surface Area
Sketch cylinder and copy table. Work together to find the S.A.
Side Area Number Sides
Total Area
Surface Area
Assignment
Side Area Number Sides
Total Area
AA
4.1m
1.9m
Sketch cylinder and copy table. Calculate S.A.
