Study Guide — Similarity and right-triangle trigonometry
Geometry
Study guide for Similarity and right-triangle trigonometry at standard high school depth.
What this standard means
- Use AA, SAS, and SSS similarity criteria
- Solve problems with similar triangles
- Define sine, cosine, and tangent for acute angles
- Apply trig ratios to find missing sides
_See printable PDF for diagram._
How to use the 20 practice sets
| Sets | When to use | | --- | --- | | 1–5 | Intro — explore together, short written items | | 6–10 | Core skills — diagrams and written practice | | 11–15 | Mixed review — explain thinking | | 16–20 | Stretch — word problems and mastery tasks |
Pacing: 10–15 minutes per session.
How to practice
1. Set up proportions from similar triangles 2. Use trig ratios in right triangles 3. Scale lengths by the similarity ratio
_See printable PDF for diagram._
Common mistakes
- Mismatching corresponding sides
- Trig ratio on wrong angle
Review and practice tests
1. Start Review 1/10 when sets 1–3 feel comfortable. 2. Move up one review level with little help. 3. Use Practice Test 4/10–6/10 for mid-standard checks. 4. Practice Test 10/10 is the mastery bar for Similarity and right-triangle trigonometry.
- [ ] Proves or identifies similarity
- [ ] Solves proportions from similar figures
- [ ] Applies trig ratios correctly
Materials for this standard
- Practice Problems — 20 printable sets
- Review — 10 difficulty levels
- Practice Test — 10 difficulty levels
- Answer key — for parents and tutors