8th Grade Slope and Similar Triangles Test with Point Values (PDF)

8th Grade math test: Slope and Similar Triangles – Maths PDF

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This slope similar triangles test for 8th Grade covers slope and similar triangles (Common Core 8.EE.B.6), with a free PDF to print.

This 20-point test checks slope from similar triangles and the equations y = mx and y = mx + b (Common Core 8.EE.B.6). Work alone, show every step, and write each final answer clearly. You have 45 minutes. Calculators are not needed unless a question says so.

Time and points

About this test

Grade: Grade 8
Chapter: Slope and Similar Triangles
Standards: 8.EE.B.6
Time: 45 minutes
Total: 20 points

Slope similar triangles test: questions

Question 1 – Find the slope [2 pts]

Find the slope through $(2, 1)$ and $(6, 9)$. (1 point)
Find the slope through $(-3, 4)$ and $(3, -2)$. (1 point)

Question 2 – Read an equation [2 pts]

State the slope and y-intercept of $y = \frac{2}{3}x – 5$. (1 point)
Rewrite $4x + 2y = 10$ as $y = mx + b$. (1 point)

Question 3 – Equation from a graph [3 pts]

A line.

Write the equation of the line.

Question 4 – Similar triangles [3 pts]

A small triangle on a line.

A larger triangle on the same line has a run of 12. Find its rise and explain why the triangles are similar.

Question 5 – Two points [3 pts]

Two points on a line.

Write the equation of the line through $(2, 7)$ and $(4, 13)$.

Question 6 – Parallel [2 pts]

A line is parallel to $y = -2x + 4$ and passes through $(0, 9)$. Write its equation.

Question 7 – Streaming [3 pts]

A streaming service charges a \$6 sign-up fee plus \$9 per month. Write an equation for the total cost $y$ after $x$ months. What are the slope and y-intercept, and what does each mean?

Question 8 – Explain [2 pts]

Ava says any two points on a line give a different slope. Use similar triangles to show she is incorrect.

Key facts behind this slope similar triangles test

Key facts

Slope $m = \frac{\text{rise}}{\text{run}} = \frac{y_{2} – y_{1}}{x_{2} – x_{1}}$.
Any two points on a line give the same slope because the triangles are similar.
$y = mx$ goes through the origin; $y = mx + b$ crosses the y-axis at $(0, b)$.
Parallel lines have equal slopes; horizontal lines have slope 0.
To write an equation, find $m$, then solve for $b$ with a point.

How to use this slope similar triangles test

Time yourself: the test is designed for an average student in 45 minutes. Answer the questions you are sure of first, then come back to the longer ones and check your units.

All Grade 8 chapters: Grade 8 math.

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