We are given two sides and an angle in between the two sides.
Recognize this?
Side-Angle-Side.
We can use the Law of Cosines to calculate the missing side.
\(c^{2} = 2^2 + 5^2 - 2 * 2 * 5 * cos(60)
c^2 = 4+25-20*cos(60)\)
\(c^2 = 4+25-20*cos(60)\)
\(c^2 = 19\)
\(c = \sqrt{19}\)
