1. Finding the Volume of Rectangular Prisms
5.MD.C.5

2. 18 cubic units Finding the Volume of Rectangular Prisms 15 16 14 17 2
Here is a rectangular prism. Let’s find the volume—or the amount of space—inside this prism.
We will use this unit cube to help measure volume. How many unit cubes will fill this shape? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
18 cubic units
The volume of this shape is 18 cubic units. 15 16 14 17 2
The volume of this shape is 18 cubic units. 13 1 18 12 5 4 3
We will use this unit cube to help measure volume. How many unit cubes will fill this shape? 6 7 11 10 9 8
Here is a rectangular prism. Let’s find the volume—or the amount of space—inside this prism.

3. Finding the Volume of Rectangular Prisms
This rectangular prism also has congruent layers.
This prism has 4 layers, and each layer has 4 unit cubes.
4 x 4 = 16. So, there are 16 unit cubes here.
This prism has 4 layers, and each layer has 4 unit cubes.
4 x 4 = 16. So, there are 16 unit cubes here.
This rectangular prism also has congruent layers.

4. 16 cubic units Finding the Volume of Rectangular Prisms
The volume of this rectangular prism is 16 cubic units.
16 cubic units
The volume of this rectangular prism is 16 cubic units.

5. 24 cubic units Finding the Volume of Rectangular Prisms
Let’s find the volume of this rectangular prism by building an identical one next to it.
The base has 6 unit cubes.
Here are 2 layers of 6 …
3 layers of 6 …
… and 4 layers of 6. Now, the prisms are identical. What is 4 x 6? 24
So, the volume of the prism is 24 cubic units.
24 cubic units
So, the volume of the prism is 24 cubic units. 24
… and 4 layers of 6. Now, the prisms are identical. What is 4 x 6?
The base has 6 unit cubes.
Here are 2 layers of 6 …
3 layers of 6 …
Let’s find the volume of this rectangular prism by building an identical one next to it.

6. 45 cubic units Finding the Volume of Rectangular Prisms 9 x 3 = 27
Let’s take apart a copy of this prism to find its volume. 3 6 9
9 x 2 = 18
9 x 3 = 27
9 x 4 = 36
9 x 5 = 45
So, the volume of this prism is 45 cubic units.
45 cubic units
9 x 3 = 27
So, the volume of this prism is 45 cubic units.
9 x 5 = 45
9 x 4 = 36 3 6 9
9 x 2 = 18
Let’s take apart a copy of this prism to find its volume.

7. Finding the Volume of Rectangular Prisms
5 × 2 × 6 = 60 6
60 cubic units
Another way to find the volume of a rectangular prism is to multiply its length by its width by its height.
How many cubes can we count across the front of the prism?
5 — the length of this prism is 5.
How many cubes are along this edge?
2 — the width of the prism is 2.
How many cubes high is the prism?
6 — the height of the prism is 6.
To find the number of unit cubes, we can multiply the length by the width by the height.
What is 5 x 2 x 6? 60
So, the volume of this prism is 60 cubic units. 2 5
What is 5 x 2 x 6? 60
So, the volume of this prism is 60 cubic units.
To find the number of unit cubes, we can multiply the length by the width by the height.
2 — the width of the prism is 2.
How many cubes can we count across the front of the prism?
Another way to find the volume of a rectangular prism is to multiply its length by its width by its height.
5 — the length of this prism is 5.
How many cubes are along this edge?
How many cubes high is the prism?
6 — the height of the prism is 6.

8. Finding the Volume of Rectangular Prisms
4 × 2 × 4 = 32 4
32 cubic units
This prism has a length of 4 …
… a width of 2 …
… and a height of 4.
We can find the volume by multiplying the length by the width by the height.
What is 4 x 2 x 4 equal to? 32
So, this prism has a volume of 32 cubic units. 2 4
So, this prism has a volume of 32 cubic units. 32
… and a height of 4.
This prism has a length of 4 …
… a width of 2 …
We can find the volume by multiplying the length by the width by the height.
What is 4 x 2 x 4 equal to?

9. Finding the Volume of Rectangular Prisms6
3 × 3 × 6 = 54
54 cubic units
This prism has a length of 3 …
… a width of 3 …
… and a height of 6.
We can find the volume by multiplying the length by the width by the height.
What is 3 x 3 x 6 equal to? 54
So, this prism has a volume of 54 cubic units. 3 3
So, this prism has a volume of 54 cubic units. 54
… and a height of 6.
This prism has a length of 3 …
… a width of 3 …
We can find the volume by multiplying the length by the width by the height.
What is 3 x 3 x 6 equal to?

10. Finding the Volume of Rectangular Prisms
Lightning Round

11. How many cubic units are there?
Finding the Volume of Rectangular Prisms
How many cubic units are there?
24 cubic units

12. How many cubic units are there?
Finding the Volume of Rectangular Prisms
How many cubic units are there?
50 cubic units

13. How many cubic units are there?
Finding the Volume of Rectangular Prisms
How many cubic units are there?
27 cubic units

14. Finding the Volume of Rectangular Prisms
Closing Question

15. How many cubic units are there?
Finding the Volume of Rectangular Prisms
How many cubic units are there?
20 cubic units