# Trigonometry Index

**Trigonometry** (from Greek trigonon "triangle" + metron "measure")

### Want to Learn Trigonometry?

Follow the links to learn.

images/circle-sine.js

### Introduction

### Sine, Cosine and Tangent

- Sine, Cosine and Tangent
- Sohcahtoa
- Sine Graph Exercise
- Graphs of Sine, Cosine and Tangent
- Unit Circle
- Interactive Unit Circle
- Sine, Cosine and Tangent in Four Quadrants
- Small Angle Approximations
- Inverse Sine, Cosine, Tangent

### Right Angled Triangles

- Solving Triangles by Reflection
- Finding an Angle in a Right Angled Triangle
- Finding a Side in a Right Angled Triangle

### Congruent and Similar

- Congruent Triangles
- Similar Triangles
- How to Find if Triangles are Similar
- Theorems about Similar Triangles
- Mean Proportional

### Solving Triangles

- Solving Triangles
- The Law of Sines
- The Law of Cosines
- The Three Angles Add to 180°
- Exterior Angle Theorem
- Solving AAA Triangles
- Solving AAS Triangles
- Solving ASA Triangles
- Solving SAS Triangles
- Solving SSA Triangles
- Solving SSS Triangles

### Area

### Identities