Practice Set · Part 1
Represent Three-Dimensional Figures in Two Dimensions
Pick up where we left off
Where we left off
Our goal: With my small group, I can find the surface area of a solid by using its net — one step at a time, with support.
The big idea: A box has 3 pairs of matching faces, so add up all 6 faces to get the surface area.
Model to copy — Watch me
- My box is 8 in. long, 5 in. wide, and 3 in. tall. I unfold it into a net and see 3 pairs of faces.
- Top and bottom: each is 8 × 5 = 40, and there are 2 of them, so 2 × 40 = 80.
- Front and back: each is 8 × 3 = 24, so 2 × 24 = 48.
- Left and right: each is 5 × 3 = 15, so 2 × 15 = 30.
- I add all the pairs: 80 + 48 + 30 = 158. The surface area is 158 in².
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.
Let's try together: Now a smaller box: 4 long, 3 wide, 2 tall. How many pairs of faces does it have? Top and bottom: 4 × 3 = 12, times 2 = 24. Front and back: 4 × 2 = 8, times 2 = 16. Left and right: 3 × 2 = 6, times 2 = 12. Now add 24 + 16 + 12. What is the surface area? Yes, SA = 52 in². Remember to use square units.My first step is ___ , because the problem asks for ___ .
Show your work - 2
Warm restartWhat is the volume of a rectangular prism with l = 4 in, w = 3 in, h = 5 in?
- A12 in³
- B60 in²
- C24 in³
- D60 in³
- 3
Warm restartA box has a base area of 12 square cm and a height of 3 cm. What is its volume?
- A36 cm³
- B15 cm³
- C4 cm³
- D36 cm²
- 4
Warm restartA box has a volume of 36 cm³. Its length is 6 cm and width is 3 cm. What is the height?
- A6 cm
- B3 cm
- C12 cm
- D2 cm
Practice Set · Part 2
Represent Three-Dimensional Figures in Two Dimensions
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 surface area of the box?
- A568 in²
- B840 in²
- C284 in²
- D280 in²
Why is that the answer?
I chose ___ because ___ .
- 6
Think it throughWhy is each face pair multiplied by 2?
- AA rectangular box has two identical faces of each size
- BBecause you always double in geometry
- CBecause there are 2 sheets of paper
- DTo convert to square inches
How do you know?
I chose ___ because ___ .
- 7
Think it throughHow many sheets of wrapping paper do you need?
- A1
- B2
- C3
- D568
Explain your thinking.
I chose ___ because ___ .
- 8
Back to the modelThe total surface area is 158 in². Which face pair contributes the most area? Why does that make sense when you look at the dimensions?
The ___ faces contribute the most area (___ in²) because their dimensions ___ × ___ = ___ are the largest. The total SA is ___ + ___ + ___ = ___ in².
Practice Set · Part 3
Represent Three-Dimensional Figures in Two Dimensions
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- The total area of every face, found by adding the faces in a net, is the ___.
- The total area of all the faces of a solid is its ___.
- A flat pattern that folds up into a solid is a ___.
- A flat surface of a solid figure is a ___.
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 Surface Area Using Nets is finding the area of only one face from each of the 3 matching pairs and forgetting to double it, instead of counting all 6 faces. - 10
Say moreFor the box l = 8, w = 5, h = 3, you found three face pairs. How did you use the net to organize the faces into pairs, and which pair had the largest area?
The faces come in ___ pairs because opposite faces are ___.
- 11
Change one numberGo back to Part 1 and pick one problem you already solved. Change one number in it, then solve your new version. Show every step.
If ___ changed to ___ , then ___ .
Show your work
Practice Set · Part 4
Represent Three-Dimensional Figures in Two Dimensions
Show what you know
Last check
These two come from Lesson 5.5. If they are shaky, that is the lesson to revisit — not this one.
- 12
Show what you knowQuick check — you've got this: A rectangular prism has l = 9 in, w = 5 in, h = 3 in. What is the surface area?
- A174 in²
- B135 in²
- C174 in³
- D87 in²
Explain your choice.
I know it is ___ because ___ .
- 13
From Lesson 5.5Quick check — you've got this: A rectangular prism has l = 11 in, w = 5 in, h = 4 in. What is the volume?
- A220 in³
- B55 in³
- C220 in²
- D200 in³
- 14
From Lesson 5.5How many more cubic inches does the large box hold?
- A4,752 in³
- B10,800 in³
- C1,728 in³
- D3,024 in³
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can find the surface area of a solid by using its net — one step at a time, with support. | |||
| I can explain why it works: A box has 3 pairs of matching faces, so add up all 6 faces to get the surface area. | |||
| I can talk through each step out loud using a sentence frame and the lesson's key words. |
One question I want to ask my group next time