Year 10 - Maths
Checking and understanding graphs showing direct proportion
Linear graphs
Study Hub
Study Guides
This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils consider equations that produce parallel or perpendicular graphs and how their equations relate to each other.
Lesson Summary
You will learn to recognise direct proportion graphically and can interpret graphs that illustrate direct proportion.
Key Notes
- Direct proportion can be recognised graphically.
- The equation of a direct proportion graph is of the form y = kx
- The origin is always a point on a direct proportion graph.
- The gradient tells us the constant of proportionality.
Vocabulary To Learn
- Direct proportion: Two variables are in direct proportion if they have a constant multiplicative relationship.
Common Mistakes To Avoid
- Direct proportion can be determined by calculating the gradient.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Direct proportion can be recognised graphically. The equation of a direct proportion graph is of the form y = kx.
2. Use this key word in a maths sentence and explain it clearly. 'Direct proportion'
Two variables are in direct proportion if they have a constant multiplicative relationship. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Direct proportion can be determined by calculating the gradient. Correction: The equation of the line should be of the form y = kx and so the y-intercept should be calculated to check it is zero.
More Lessons In This Unit
- Advanced problem solving with linear graphs Study Guide
- Checking and securing understanding of drawing linear graphs Study Guide
- Checking and securing understanding of drawing vertical and horizontal graphs Study Guide
- Checking and securing understanding of finding the equation of the line from coordinates Study Guide
- Checking and securing understanding of finding the equation of the line from the graph Study Guide
- Graphs showing inverse proportion Study Guide
- Identifying perpendicular linear graphs Study Guide
- Parallel and perpendicular lines on coordinate axes Study Guide
- Parallel linear graphs Study Guide
- Perpendicular linear graphs Study Guide
- Problem solving with linear graphs Study Guide
- Ratios in line segments on coordinate axes Study Guide
Browse all guides in the Year 10 Maths guide library.