Law of Cosines

the worst shit you could ever witness in solving oblique triangles; more painful than Law of Sine.

“Dude, are why the fuck do we even have LAW OF COSINES”

“idk bro but it's lowkey fun, here r the formulas”

Formulas FOR SIDES:
a² = b²+c²-2bc cosA
b²= a²+c²-2ac cos B
c²= a²+b²-2ab cos C

Formulas FOR SIDES: (always use cos-¹ to solve for angles)

cosA : b²+c²-a² / 2bc
cosB: a²+c²-b²/ 2ac
cosC: a² + b² / 2ab

by kumicakes September 23, 2025