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# Surface area review

Review surface area and try some practice problems.

## What is surface area?

**Surface area**is the amount of space covering the outside of a three-dimensional shape.

## Finding surface area

To calculate surface area, we add the areas of all the faces of the three-dimensional figure.

*Want to learn more about finding surface area? Check out this video.*

### Example: Rectangular prism

**Find the surface area of the right rectangular prism shown below.**

Let's draw a net of the rectangular prism.

Each of the sides is a 4 by 1, point, 5 rectangle.

The total area of both sides is 2, dot, 6, equals, start color #11accd, 12, end color #11accd.

The bottom and the top are both 4 by 5 rectangles.

The total area of bottom and the top is 2, dot, 20, equals, start color #1fab54, 40, end color #1fab54.

The back and the front are both 1, point, 5 by 5 rectangles.

The total area of the back and the front is 2, dot, 7, point, 5, equals, start color #e07d10, 15, end color #e07d10.

Let's add the areas to find the surface area.

**The surface area of the rectangular prism is 67 unitssquared.**

## Want to join the conversation?

- How do you find the surface area of a cylinder??(94 votes)
- Actually if the radius is r, the surface area is 4*pi*r^2(43 votes)

- Would it be possible to find the surface area of a sphere?(32 votes)
- if the radius is r, the surface area is 4*pi*r^2(22 votes)

- the question to find the surface area of a square with sides 2 1/2 confuses me. can someone please explain in detail how to solve this problem?(20 votes)
- Basically, 2 1/2 equals 2.5. So the easiest way to do that is obviously by multiplying 2.5*2.5*6 By the way, * equals multiply.(19 votes)

- What if we don't have a decimal and just a normal number?(12 votes)
- That's ok, you won't always get a decimal or fraction.

Hope this helps, have a great day.(15 votes)

- How do you find the surface area of a cylinder(12 votes)
- The total surface area of the cylinder formula is the sum of the base surface area and the lateral surface area: total_area = base_area + lateral_area , or total_area = 2 * π * r² + (2 * π * r) * h , or total_area = 2 * π * r * (r + h) .(5 votes)

- How about to find the surface area of a hyperboloid?(13 votes)
- How do you find the height of a cuboid, when the length, the width and the surface area is given?(10 votes)
- Surface area of cuboid = 2(lb+bh+hl)

So you put the values and then solve.(9 votes)

- how to find the area of a square pyramid?(10 votes)
- I assume you mean the surface area, since a square pyramid is 3-dimensional.

For a right square pyramid with base side length s and slant height L, the total surface area is the area of the square base with side length s, plus the total area of four triangles each with base s and altitude L. So the total surface area is

s^2 + 4(1/2)(sL) = s^2 + 2sL.

(Note well: the slant height is**not**the same as the vertical height.)(9 votes)

- I Get it but I still need help and a little bit of practice(13 votes)
- Why are questions called quetions... The more you know.........The less you are(12 votes)
- why is this so funny to me? anybody else??(1 vote)