Geometry Similar Triangle Theorems Test with Point Values (PDF)
This similar triangles test for Geometry covers similar triangle theorems (Common Core G-SRT.B.4, G-SRT.B.5), with a free PDF to print.
Time and points
- Grade: Geometry
- Chapter: Similar Triangle Theorems
- Standards: G-SRT.B.4, G-SRT.B.5
- Time: 45 minutes
- Total: 20 points
Similar triangles test: questions
Question 1 – Triangle proportionality [2 pts]
DE is parallel to BC. AD = x, DB = 12, AE = 10 and EC = 15. Find x and AB.
Question 2 – Is it parallel? [2 pts]
In triangle ABC, D is on AB and E is on AC with AD = 6, DB = 8, AE = 9 and EC = 12. Is DE parallel to BC? Explain.
Question 3 – Altitude to the hypotenuse [3 pts]
- Find the hypotenuse. (1 point)
- Find the segments AD and DB of the hypotenuse. (1 point)
- Find the altitude h. (1 point)
Question 4 – SSS similarity [2 pts]
Triangle ABC has sides 9, 12 and 15. Triangle DEF has sides 6, 8 and 10. Are they similar? If so, name the test and the scale factor from DEF to ABC.
Question 5 – Solve for x [2 pts]
DE is parallel to BC. AD = 2x, DB = x + 6, AE = 9 and EC = 6. Find x and AD.
Question 6 – Prove similar [3 pts]
DE is parallel to BC. Explain why triangle ADE is similar to triangle ABC. Then find DE if AD = 4, AB = 10 and BC = 15.
Question 7 – Geometric mean [2 pts]
Find the geometric mean of 6 and 24. Then find the length of the altitude to the hypotenuse if it splits the hypotenuse into segments of 6 and 24.
Question 8 – Mirror method [2 pts]
A mirror is on the ground 10 feet from a student whose eye is 5 feet high. The mirror is 40 feet from a tower. Find the height of the tower.
Question 9 – Similar areas [2 pts]
Two similar triangles have corresponding sides of 4 and 10. The larger has area 125. Find the area of the smaller triangle.
Key facts behind this similar triangles test
- Triangle Proportionality: DE parallel to BC gives AD/DB = AE/EC.
- Triangle similarity tests: AA, SAS~ and SSS~.
- Altitude to the hypotenuse: h squared = p times q.
- Leg relationship: a squared = p times c.
- Similar triangles let you measure heights and widths indirectly.
How to use this 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 Geometry chapters: Geometry math.
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