| M5 Home Page |
| All About Circuits | Trigonometric Equivalencies |
| Cuthbert Nyack | Trigonometric Relations |
| Math.com | Trigonometric Identities |
| Wolfram Research | Law of Sines |
| Integrated Publishing | Distance from a Point to a Line |
| Math.com | Trigonometric Tables |
| University of Vienna | Triangle and Law of Sines |
| Algebra Lab | Basic Trig Identities |