Ordering topics in a logical sequence
It might help users if the information on this page was put in some progressive order of development.
For example like this sequence:
Ratio Equivalent ratios Protractor and Scale Drawings Rounding-off decimals Tangent ratio Sine ratio Cosine ratio Trigonometric tables Inverse ratios Coordinate system trigonometry Obtuse angle sine and cosine ratios Extending to the sine and cosine functions Tangent function Inverse functions Identities Sine law Cosine law Cosine of the difference of two angles identity Negative angle measurements Sum and difference identities Graphing part 1 Graphing part 2 Radian ratios
(This is the sequence I used in a 1971 textbook to promote an inductive teaching approach to trigonometry.)
Jim Kelly (k-12math.info)