Practice Set · Part 1
Determine the Volume of Rectangular Prisms
Pick up where we left off
Where we left off
Our goal: I can find the volume of a rectangular prism with whole-number edges using length × width × height, explain why the method works, and use it on a problem I have not seen before.
The big idea: Volume is base area times height, so dividing the volume by the base area tells how many layers tall the box is.
Model to copy — Example · Find a missing height
- A storage box has a volume of 120 cubic inches. It is 6 inches long and 5 inches wide. How tall is it?
- Find the area of the base: 6 × 5 = 30
- Write the volume with the missing height: 120 = 30 × h
- Divide the volume by the base area: 120 ÷ 30 = 4
- Check by multiplying: 6 × 5 × 4 = 120
- The box is 4 inches tall.
Start here
You did these with your group. Now do them on your own — the model above is yours to copy.
- 1
Same stepsFinish what the group started. Use the model above, step for step.
Try it together — then prove it: A box is 5 units long, 2 units wide, and 2 units tall. Find its volume. Find the volume. (5 × 2 × 2 = 20 cubic units) How many cubes are in one layer? How many layers? (10 cubes in a layer, and 2 layers) Why is the answer in cubic units, not square units? (Volume fills space in 3 directions: length, width and height. Each unit is a small cube.)Show your work - 2
Warm restartTo find the area of a composite figure, you first…
- Ameasure around the outside
- Bmultiply all the side lengths
- Cfind the longest side
- Dbreak it into basic shapes you know
How do you know?
- 3
Warm restartA figure is a 6 by 4 rectangle with a 2 by 3 rectangle attached. What is the total area?
- A15 square units
- B24 square units
- C30 square units
- D144 square units
How do you know?
- 4
Warm restartA 10 by 8 rectangular garden has a 3 by 3 square patio cut out of it. What area is left?
- A62 square units
- B71 square units
- C80 square units
- D89 square units
How do you know?
Practice Set · Part 2
Determine the Volume of Rectangular Prisms
Keep going
You answered these out loud. Now write them.
Answer, then say how you know — the reason is the part that counts.
- 5
Think it throughWhat is the volume of the large box?
- A60 in³
- B3,024 in³
- C4,752 in³
- D7,776 in³
Why is that the answer?
- 6
Think it throughWhat is the volume of the medium box?
- A2,520 in³
- B3,024 in³
- C3,240 in³
- D4,752 in³
How do you know? Give a second reason as well.
- 7
Think it throughHow many more cubic inches does the large box hold?
- A1,728 in³
- B3,024 in³
- C4,752 in³
- D10,800 in³
Explain your thinking. What would have to change for a different choice to be right?
- 8
Back to the modelContainer C holds the most (96 in³) and Container B holds the least (50 in³). What do you notice about the dimensions that make one volume larger than another?
Practice Set · Part 3
Determine the Volume of Rectangular Prisms
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- The amount of space inside a three-dimensional solid is its ___.
- A solid with six rectangular faces, like a box, is a ___.
- The unit used to measure volume, like cubic centimeters, is ___.
- The three edge measurements of a rectangular prism are its ___.
Explain the thinking
- 9
Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.
The mistake: A common mistake in Volume with Whole Number Edges is multiplying only two of the three edges and stopping there — for example, seeing a box that is 6 in long, 4 in wide, and 3 in tall, multiplying just 6 × 4 = 24, and calling that the volume, when 24 is only the area of the bottom face (in square inches), not the volume of the whole box. - 10
Say moreContainer C is 8 × 3 × 4 and Container B is 5 × 5 × 2. How did you count or multiply the unit cubes to find each volume, and which holds more?
- 11
Write your ownWrite your own problem about this situation, then solve it and show the answer. The situation: Two time capsule containers sit side by side. Capsule A is 4 in long, 3 in wide, and 8 in tall. Capsule B is 6 in long, 6 in wide, and 6 in tall. A classmate says Capsule A must hold more because it looks taller.
Show your work
Practice Set · Part 4
Determine the Volume of Rectangular Prisms
Show what you know
Last check
These two come from Lesson 5.4. If they are shaky, that is the lesson to revisit — not this one.
- 12
Show what you knowExplain your thinking — A rectangular prism has l = 11 in, w = 5 in, h = 4 in. What is the volume?
- A55 in³
- B200 in³
- C220 in³
- D220 in²
Explain your choice.
- 13
From Lesson 5.4Explain your thinking — A composite figure is made of a 9 ft x 7 ft rectangle and a 3 ft x 4 ft rectangle joined together. What is the total area?
- A12 sq ft
- B63 sq ft
- C75 sq ft
- D75 ft
How do you know?
- 14
From Lesson 5.4What will the carpet cost?
- A$116
- B$300
- C$580
- D$1,160
How do you know?
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can find the volume of a rectangular prism with whole-number edges using length × width × height, explain why the method works, and use it on a problem I have not seen before. | |||
| I can explain why it works: Volume is base area times height, so dividing the volume by the base area tells how many layers tall the box… | |||
| I can justify my answer to a skeptic and connect it to a second strategy or representation. |
One question I want to ask my group next time