Sine Law and Cosine Law

Although we often deal with right-angled triangles, many triangles do not have a right angle. The Sine Law and Cosine Law are often useful for those triangles.


Sine Law:
sin(θa)
a
=
sin(θb)
b
=
sin(θc)
c

Cosine Law:
c2 = a2 + b2 - 2ab cos(θc)