1. Finding the Volume of Irregular Shapes 5.MD.C.5

2. Here is a prism that is not rectangular.We can find its volume by counting the number of unit cubes needed to completely fill it.1234510152025The volume of this shape is 25 cubic units. 25 cubic units Finding the Volume of Irregular Shapes

3. Let’s find the volume of this prism by building an identical copy.1234566 x 2 = 126 x 3 = 186 x 4 = 24The volume of this shape is 24 cubic units. 24 cubic units Finding the Volume of Irregular Shapes

4. We can also find the volume of a prism by subtracting cubes.Here is an exact copy of the prism. Let’s subtract and count unit cubes.12345672 sets of 7 is 14.3 sets of 7 is 21.And, 4 sets of 7 is 28.The volume of this prism is 28 cubic units. 28 cubic units Finding the Volume of Irregular Shapes

5. Let’s build a copy of this prism to find its volume.24681020304050The volume of the prism is 50 cubic units. 50 cubic units Finding the Volume of Irregular Shapes

6. 2 3 5 2 2 5 203050 50 cubic units Another way to find the volume of an irregular prism is to decompose it into rectangular prisms.Now, let’s find the volume of each prism. Then, we can add them together.The first prism has a length of 2 …… a width of 2 …… and a height of 5. So, how many unit cubes make up the first prism?20The second prism has a length of 2 …… a width of 3 …… and a height of 5. So, how many unit cubes make up the second prism?How many unit cubes are there in all?50 += 30 Finding the Volume of Irregular Shapes

7. 50 cubic units This prism has a volume of 50 cubic units. Finding the Volume of Irregular Shapes

8. Here is another prism that is not a rectangular prism. Finding the Volume of Irregular Shapes

9. But, we can break it into multiple rectangular prisms. Finding the Volume of Irregular Shapes

10. 52 cubic units 2 2 4 16 3 2 2 12 2 2 6 24++=52 Let’s separate the rectangular prisms.Now, we can find the volume of each part.How many units cubes make up the first prism?16How many units cubes make up the next prism?12How many units cubes make up the last prism?24Now, what is the sum of all the unit cubes?52The entire volume is 52 cubic units. Finding the Volume of Irregular Shapes

11. 52 cubic units Now, let’s put the prisms back together. Finding the Volume of Irregular Shapes

12. 52 cubic units The volume of this prism is 52 cubic units. Finding the Volume of Irregular Shapes

13. Here is another shape that has volume, but is not a rectangular prism.Let’s break it into rectangular prisms. Finding the Volume of Irregular Shapes

14. 36 cubic units 2 4 3 24 1 1 4 4 2 2 2 8++=36 Now, let’s find the volume of each part.How many units cubes make up the first prism?24How many units cubes make up the next prism?4How many units cubes make up the last prism?8Now, what is the sum of all the unit cubes?36The entire volume is 36 cubic units. Finding the Volume of Irregular Shapes

15. 36 cubic units Now, let’s put the prisms back together. Finding the Volume of Irregular Shapes

16. The volume of this shape is 36 cubic units. 36 cubic units Finding the Volume of Irregular Shapes

17. Lightning Round

18. How many cubic units are there? 15 cubic units Finding the Volume of Irregular Shapes

19. 10 cubic units How many cubic units are there? Finding the Volume of Irregular Shapes

20. 34 cubic units How many cubic units are there? Finding the Volume of Irregular Shapes

21. Closing Question Finding the Volume of Irregular Shapes

22. 36 cubic units How many cubic units are there? Finding the Volume of Irregular Shapes