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### Course: 6th grade (Illustrative Mathematics) > Unit 1

Lesson 11: Extra practice: Surface area# Surface area versus volume

A 3D figure has both surface area and volume measurements, but we use them for different purposes. Learn the difference and when to use each.

## Making sense of units

We have many types of units. Some measure length in $1$ dimension. Some measure area in $2$ dimensions. Others measure volume in $3$ dimensions. Units come in larger and smaller sizes, too.

## Key measurement terms

**Length**is a

*units*between one point and another. We measure length in units like centimeters, inches, feet, meters, kilometers, and miles.

**Perimeter**is a special example of length. It is the distance around a closed 2D figure.

**Area**is a

*square units*such as square centimeters (

**Surface area**is a special example of area. It tells us the number of*square units*it would take to cover the faces of the 3D figure.

**Volume**is a

*cubic units*it would take to fill a 3D figure. We measure volume in units like cubic centimeters

Notice, this means that we can measure both the surface area and the volume of a 3D figure, but they tell us different things about the figure.

## Distinguishing area and volume

Let's consider the same situations from before, this time to decide whether which type of measurement makes the most sense.

The same 3D figure can have both surface area and volume.

Let's contrast the volume and surface area of two figures.

So the figures have the same volume, but different surface areas!

The opposite is possible, too. Two figures could have the same surface area, but different volumes.

## Try it out!

## Want to join the conversation?

- why the Surface area is 32(10 votes)
- idk but i also got 32 on the first try by adding the 4 middle parts(4 votes)

- What the heck is this its so hard🥲(10 votes)
- ikr why do we need to learn this(3 votes)

- I was kind of confused after reading and doing the practice, so I had to redo it three times over. Worth it though, compared to other curriculums I've done. Is there a way I can learn to understand surface area versus volume better?(8 votes)
- this dont make sence(9 votes)
- if you pay attention it does(0 votes)

- why is it LITTARLY so hard to do and even understand?(8 votes)
- You should ask your teacher for more help if you don't understand(0 votes)

- i dont understand how to find the surface area of the 3d shape with a hole in it(4 votes)
- look at the whole and notice that it has 4 faces surrounding it. Find the surface area like you normally would then add the 4 faces to the equation. The equation would look something like this: A=8+8+3+3+3+3+1+1+1+1.(5 votes)

- If anyone can tell me which question dose not make sense to you I am glad to help!(5 votes)
- What is 3x3x3x3x3x3x3x3x3x3x3x3(4 votes)
- 3x3x3x3x3x3x3x3x3x3x3x3= 531441(5 votes)

- I hate math so much(5 votes)
- I dont know what to ask(5 votes)