MathQuizily ranked #372 in TIME and Statista's World's Top EdTech Companies 2026.Read the announcement

What Is the Slope of a Line?(With Examples)

Slope measures the steepness and direction of a line. It tells you how much the line rises (or falls) for each unit it moves horizontally. Slope is often described as "rise over run" - the vertical change divided by the horizontal change.

Grade 8Key Stage 3-4Årskurs 8-9Klasse 8

📖Definition

Slope measures the steepness and direction of a line. It tells you how much the line rises (or falls) for each unit it moves horizontally. Slope is often described as "rise over run" - the vertical change divided by the horizontal change.

📐Formula

m = (y₂ - y₁) / (x₂ - x₁) = rise / run

To find slope between two points (x₁, y₁) and (x₂, y₂): subtract the y-values (rise) and divide by the difference in x-values (run). In y = mx + b, m is the slope.

📝Step-by-Step Guide

1

Identify Two Points

Find two points on the line with coordinates (x₁, y₁) and (x₂, y₂).

2

Calculate Rise

Subtract the y-coordinates: rise = y₂ - y₁.

3

Calculate Run

Subtract the x-coordinates: run = x₂ - x₁.

4

Divide Rise by Run

Slope = rise ÷ run. Simplify if possible.

m = (y₂ - y₁) / (x₂ - x₁)

⚠️Common Mistakes to Avoid

  • Subtracting in different orders (y₂-y₁ but x₁-x₂)
  • Confusing rise and run
  • Dividing run by rise instead of rise by run
  • Forgetting that vertical lines have undefined slope
  • Thinking horizontal lines have undefined slope (they have slope 0)

✏️Practice Problems

Easy

Find the slope between (1, 2) and (3, 6)

Answer: m = 2

Medium

Find the slope between (-2, 5) and (4, -1)

Answer: m = -1

Hard

A line passes through (3, -2) and has slope 2/3. Find y when x = 9.

Answer: y = 2

Printable Slope of a Line practice

Need more than a few examples? Create a printable slope of a line test with a worked answer key, balanced difficulty, and a teacher-reviewed PDF.

Ready to Practice Slope of a Line?

Generate a personalized practice test with MathQuizily. Get instant PDF downloads with answer keys.

Worked Examples

Curriculum Alignment

CommonCore (8.EE.B.6)KS3KMK

Classroom assessment context

Build the assessment, not just the questions

MathQuizily helps teachers move from a topic or standard to a printable math test with answer keys, balanced difficulty, and classroom-ready PDF output.

A useful assessment should make the learning target clear, cover the intended skills, and give the teacher enough information to review the result before students see it. The workflow supports short quizzes, chapter checks, diagnostic tests, homework packets, make-up assessments, and equivalent retake versions.

Choose a grade, topic, curriculum context, and difficulty level. The generated PDF includes a student version and a separate worked answer key, so teachers can print, review, and grade without reformatting questions or building solutions from scratch. No student account is required to create or print a test.