What is the angle in degrees from the x-axis is the resultant of a system of forces, if F1 = F2 = F3 = F4?

Immediately after payment you will receive a link to the zip file with the task 2.2.20 (Chapter 1 - statics topic - 2.2: The main vector and the main moment of plane system of forces. Bringing to the simplest form.) In theoretical mechanics from the collection of short tasks Kep O. E., JA Viba, OP Grapis, JA Svetinysh and others. Publishing Moscow / Graduate School / 1989, 2009, 2012. The task is made in the format word (typed or hand-written decision in a Word) or in manuscript form in the format gif, packed to the archive zip (open on any PC) .After checking the solutions would be very grateful if you leave your positive feedback.