Hey dudes (and dudettes).

I actually know how to solve this problem, however the authors provide their answers in a different format (groups of square roots) whereas I just solve to the nearest hundredth using trig functions. I don't understand where the authors get their square root values from in the solution, and it's relevant that I know as it's likely the same solution format will be tested in the exam. Could someone please clarify this for me?

Thanks as always.