IXL | Surface area of cylinders

What is the surface area of this cylinder?

Round your answer to the nearest hundredth.

5 ft

10 ft

square feet

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Learn with an example

question

What is the surface area of this cylinder?

Round your answer to the nearest hundredth.

4 in

3 in

square inches

key idea

Surface area of a cylinder:

Surface area

A_top + A_bottom + A_side

solution

Find the radius and height of the cylinder.

radius	=	4

height	=	3

Find the area of the circle on the top of the cylinder. Use 3.14 for 𝜋.

A_top

𝜋r²

≈

3.14 × 4 × 4

≈

50.24

The circle on the bottom of the cylinder is the same, so:

A_bottom

A_top ≈ 50.24

Find the circumference of the top circle.

2𝜋r

≈

2 × 3.14 × 4

≈

25.12

Now find the area of the curved surface. The curved surface is a rectangle. One side length is the height, and the other side length is the circumference of the circle.

A_side

≈

25.12

≈

75.36

Now add the areas to find the surface area of the cylinder.

Surface area

A_top + A_bottom + A_side

≈

50.24 + 50.24 + 75.36

≈

175.84

The surface area of the cylinder is about 175.84 square inches.

Looking for more? Try these:

Lesson: Surface area formulas

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Lesson: Surface area formulas

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