Students may use this computer applet to explore angle sums of triangle, quadrilaterals, pentagons and hexagons.

Use Glencoe's Math Course 2 randomly generated self-checking quiz to test your knowledge of a variety of triangle topics. Each question has a "Hint" link to help. Choose the correct answer for each problem. At the bottom of the page...

Finding the third angle of a triangle becomes easier by the explanation and examples presented.

The University of Saskatchewan provides an explanation of trigonometric identities, including the reciprocal identities, the addition and subtraction formulas with sine and cosine, and the double angle formulas. There are links to...

Find a quick, concise explanation of the Angle Sum Theorem. A step by step explanation of the proof is included to help you understand the theorem.

In addition to understanding the concept of similar right triangles and how they apply to trigonometric ratios, young scholars explore a clinometer app, and discover how it can be used to test the mathematics underpinning trigonometry.

This site is a quick review of the functions and identities in trigonometry. Very helpful site.

Just about everything you need to know about trigonometry can be found here. Interactive examples and demonstrations help to enhance the lessons. Although not required, the tutorial uses Live Math and Scientific Notebook.