Similar Triangles Proportions Quiz – Geometry (10 Questions)

Last updated: October 22, 2026 · Written by the Math Made Easy math teachers

Standards: G-SRT.B.4, G-SRT.B.5 · Level: Grade 10 Geometry

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What this Similar Triangles, Proportions and Indirect Measurement quiz checks

• AA, SAS and SSS similarity criteria prove triangles similar.
• A line parallel to a side divides the other two sides proportionally, and the converse is true.
• In a right triangle, the altitude to the hypotenuse satisfies h² = p · q.
• Each leg is the geometric mean of the hypotenuse and the adjacent segment: a² = p · c.
• Similar triangles let you measure heights and distances indirectly.

The 10 questions of the quiz

1. △ABC ∼ △DEF, with AB = 4, DE = 10 and BC = 6. What is EF?
2. DE ∥ BC. AD = 4, DB = 6 and AE = 6. What is EC?
3. Triangle 1 has sides 6, 8 and 10. Triangle 2 has sides 9, 12 and 15. Which criterion proves them similar?
4. The altitude to the hypotenuse of a right triangle splits it into pieces of 4 and 9. How long is the altitude?
5. What is the geometric mean of 6 and 54?
6. In the right triangle, which similarity statement is correct?
7. AD/DB = AE/EC in △ABC, with D on AB and E on AC. What follows?
8. A student with eye height 1.6 m stands 2 m from a mirror on the ground. The mirror is 25 m from a tree. How tall is the tree?
9. Which is NOT a valid way to prove two triangles similar?
10. In a right triangle, a leg is 15 and the hypotenuse is 25. How long is the piece of the hypotenuse next to that leg?

After the quiz

Missed a question? Reread the Similar Triangles, Proportions and Indirect Measurement lesson, then take the quiz again. Next, solve the Geometry worksheet on Similar Triangles, Proportions and Indirect Measurement, one star first, then two and three stars. Finally, take the chapter test under real conditions, without notes and with a timer.