Schoolcraft College
Trigonometry
This trigonometry textbook takes the learner from a basic understanding of angles and triangles through the use of polar coordinates on the complex plane. Written by a mathematician-engineer, examples and problems here are used to...
EngageNY
An Area Formula for Triangles
Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....