Practice Set · Part 1
Determine Distance on the Coordinate Plane
Pick up where we left off
Where we left off
Our goal: I can find the distance between two points on the coordinate plane using absolute value, explain why the method works, and use it on a problem I have not seen before.
The big idea: Check the signs before you compute, because the same side of 0 means subtract absolute values and opposite sides means add them.
Model to copy — Example · Two negative coordinates
- Find the distance between (−4, −1) and (−4, −6).
- Find the coordinate that is the same: x = −4 for both
- Look at the signs of the y-coordinates: −1 and −6
- Find each distance from 0: |−1| = 1 → |−6| = 6
- Subtract the smaller distance from the larger: 6 − 1 = 5
- The distance is 5 units. Adding 1 + 6 = 7 would be wrong.
Start here
Use the model to solve the first problem. Then try these quick review questions from earlier lessons.
- 1
Same stepsFinish what the group started. Use the model above, step for step.
Try it together — then prove it:- Find the distance between (2, 3) and (2, 8).
- Which coordinate is the same? Which way does the line go? (x = 2, so the line goes up and down.)
- Find the distance. (8 − 3 = 5 units)
- Why do we subtract here, and not add? (Both points are on the same side of 0. The 3 units to (2, 3) are part of the 8 units to (2, 8).)
Show your work - 2
Quick reviewIn which quadrant is the point (-4, 5)?
- AQuadrant I
- BQuadrant III
- CQuadrant II
- DQuadrant IV
How do you know?
- 3
Quick reviewWhich point is located on the x-axis?
- A(-4, -4)
- B(0, 4)
- C(4, 4)
- D(4, 0)
How do you know?
- 4
Quick reviewA point has a positive x-coordinate and a negative y-coordinate. Which quadrant is it in?
- AQuadrant I
- BQuadrant II
- CQuadrant IV
- DQuadrant III
How do you know?
Practice Set · Part 2
Determine Distance on the Coordinate Plane
Keep going
Try these on your own
Choose an answer. Then explain how you know.
- 5
Think it throughWhat is the horizontal distance from (−4, 0) to (3, 0)?
- A1 unit
- B−1 unit
- C7 units
- D12 units
Why is that the answer?
- 6
Think it throughWhat is the vertical distance from (3, 0) to (3, −5)?
- A3 units
- B5 units
- C−5 units
- D8 units
How do you know? Give a second reason as well.
- 7
Think it throughWhat is the total flight path?
- A2 units
- B7 units
- C12 units
- D35 units
Explain your thinking. What would have to change for a different choice to be right?
- 8
Back to the modelHow did you use coordinates and absolute value to find the distance between two points in the same row or column?
Practice Set · Part 3
Determine Distance on the Coordinate Plane
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- How far apart two points are on the coordinate plane is the ___.
- The distance of a number from zero, used to find distance between points, is its ___.
- The distance between two points along the x-direction is the ___.
- The distance between two points along the y-direction is the ___.
Explain the thinking
- 9
Find the mistakeRead the mistake. Explain what went wrong, then show the correct step.
The mistake: A common mistake in Distance on the Coordinate Plane is subtracting the coordinates as if both points were on the same side of zero, instead of adding their absolute values when the points are on opposite sides. - 10
Say moreOne point is at (-3, 1) and another is at (4, 1). How does absolute value help you find the distance across zero?
- 11
Write your ownWrite your own problem about this situation, then solve it and show the answer. The situation: Tahira will walk from the middle school to the high school. The grid shows a map of the town, where each unit labeled on the grid represents one kilometer.
Show your work
Practice Set · Part 4
Determine Distance on the Coordinate Plane
Show what you know
Last check
These two come from Lesson 7.5. If they are shaky, that is the lesson to revisit — not this one.
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Show what you knowExplain your thinking — What is the distance between the points (3, -2) and (3, 5)?
- A3 units
- B5 units
- C7 units
- D9 units
Explain your choice.
- 13
From Lesson 7.5Explain your thinking — Point P is located 6 units right and 3 units up from the origin. What ordered pair names point P?
- A(0, 3)
- B(3, 6)
- C(6, 3)
- D(6, 0)
How do you know?
- 14
From Lesson 7.5Which point is farthest to the right?
- A(3, 6)
- B(0, 0)
- C(8, 2)
- DThey are all the same
How do you know?
Check your progress
Choose the box that best describes how you feel about each skill.
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can find the distance between two points on the coordinate plane using absolute value, explain why the method works, and use it on a problem I have not seen before. | |||
| I can explain why it works: Check the signs before you compute, because the same side of 0 means subtract absolute values and opposite… | |||
| 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