The Cosine Theorem
- Author:
- s-tefan
The figure illustrates and proves the Cosine Theorem for acute triangles.
Find out how this figure proves the Cosine Theorem for triangles, which states a relation between lengths of the the three sides of a triangle and the cosine of one of the angles. You can move the corners to change the dimensions of the triangle. (The figure works well only if all angles are acute, though.)