What Are the Applications of the Law of Cosines?
TL;DR: Got a triangle that refuses to be a right triangle? The Law of Cosines has your back: c squared equals a squared plus b squared minus 2ab times cosine of C. Notice it looks like the Pythagorean theorem with a correction term tacked on — and when angle C is 90 degrees, that cosine […]
How to Use Derivation of the Law of Cosines
TL;DR: Wondering where the Law of Cosines actually comes from? Drop an altitude inside a general triangle, splitting it into two right triangles, then apply the Pythagorean theorem twice and do a bit of algebra cleanup. Out pops c squared equals a squared plus b squared minus 2ab times cosine of C. The point isn’t […]
