Graphing Relationships from Tables
A free Pre-Algebra lesson from the “Proportional Reasoning” unit, with a worked example and practice problems including step-by-step solutions.
A table can become a graph by turning each row into an ordered pair. In a proportional relationship, the graph is a straight line through the origin because every output is a constant multiple of the input.
What you'll learn
- Create ordered pairs from tables
- Identify patterns in graphs
- Connect proportional relationships to straight lines
Worked example
Problem. A table follows y = 2x. What point matches x = 5?
- Use x = 5 in y = 2x.
- y = 2 x 5 = 10.
- The ordered pair is (5, 10).
Answer: (5, 10)
Practice problems
1. Which ordered pair comes from x = 3 and y = 8?
Choices: (3, 8) · (8, 3) · (3, 3) · (8, 8)
Show solution
- Warm-up: First identify exactly what the question is asking: Which ordered pair comes from x = 3 and y = 8?
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Ordered pairs are written (x, y).
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: (3, 8)
2. For y = 5x, what is y when x = 4?
Show solution
- Warm-up: First identify exactly what the question is asking: For y = 5x, what is y when x = 4?
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Substitute x = 4.
- 5 x 4 = 20.
- Check the result by substituting or estimating: the response should match 20 and make sense in the original problem.
Answer: 20
3. Which point must be on every proportional graph?
Choices: (0, 0) · (1, 0) · (0, 1) · (1, 1)
Show solution
- Warm-up: First identify exactly what the question is asking: Which point must be on every proportional graph?
- Compare each answer choice with the calculation or rule, and eliminate choices that do not satisfy the condition.
- A proportional relationship has the form y = kx.
- When x = 0, y = 0.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: (0, 0)
4. A table has x: 1, 2, 3 and y: 4, 8, 12. What is the constant of proportionality?
Show solution
- Core Practice: First identify exactly what the question is asking: A table has x: 1, 2, 3 and y: 4, 8, 12. What is the constant of proportionality?
- Choose the operation or relationship that matches the wording, then carry it out one clear step at a time.
- Divide y by x for any row.
- 4 divided by 1 is 4, and 8 divided by 2 is 4.
- Check the result by substituting or estimating: the response should match 4 and make sense in the original problem.
Answer: 4
5. Which point fits y = 3x?
Choices: (4, 12) · (4, 7) · (12, 4) · (3, 4)
Show solution
- Core Practice: First identify exactly what the question is asking: Which point fits y = 3x?
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- If x = 4, then y = 3 x 4 = 12.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: (4, 12)
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