Question

A triangle has sides A, B, and C. Sides A and B are of lengths `12` and `8`, respectively, and the angle between A and B is `(11pi)/12`. What is the length of side C?

Answer 1

`c = 19.8`

Explanation:

Law of Cosines equation is `c^2 = a^2 + b^2 – 2*a*b*cos(gamma)`.

`c^2 = 12^2 + 8^2 – 2*12*8*cos(11π/12)`.
`c^2 = 144 + 64 – 192*(-0.966)`.
`c^2 = 393.5` : `c = 19.8`