PYTHAGOREAN THEOREM

Titles are: THE COSINE FORMULA. Shows how the Pythagorean Theorem formula can be applied to acute angled triangles in addition to right triangles and how this leads to the cosine formula. Animation shows that as the acute angle approaches a right angle, its cosine approaches zero, so that the Pythagorean Theorem re-appears; PROOF BY AREA. Animated diagrams demonstrate the principles of geometric movement and transformation, to show how the square of each side of a right triangle may be transformed to a parallelogram of equal area, and how these may be proved to be equal in area to the square of the hypotentuse