Law of Cosine
Do you know!!!
Formula for Law of Cosine
c^2 = a^2 + b^2 - 2ab cos(C)
b^2 = a^2 + c^2 - 2ac cos(B)
a^2 + b^2 + c^2 - 2bc cos(A)
When do you use this?
You use the Law of Cosine for finding a missing side for a triangle, or a missing angle.
Examplessssssssssssssssss!!
In the triangle ABC, side b = 12, side c = 20, and m < A = 40 degrees. Find side A to the nearest interger.
a^2 = 12^2 + 20^2 - 2(12)(20)(cos 40)
a^2 = 144 + 400 - 480(.7660)
a^2 = 176.2988
a = 13.2777 about 13