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.
[tex] c^{2} = 2^2 + 5^2 - 2 * 2 * 5 * cos(60)
c^2 = 4+25-20*cos(60)
[/tex]
[tex] c^2 = 4+25-20*cos(60)[/tex]
[tex]c^2 = 19[/tex]
[tex]c = \sqrt{19}[/tex]
