I should slap myself for not picking out what I did wrong but... 500 N are acting 140 degrees, 150 N are acting at 90 degrees and 420 N are acting at 60 degrees. Find the resultant. the Resultant = (Rx^2 + Ry^2)^(1/2) The angle of the resultant = arctan(Fy/Fx) Correct? Well, Fx = -500cos40 + 150cos90 + 420cos60 = -173.02222 Fy = 500sin40 + 150sin90 + 420sin60 = 835.12447. Resultant = ((8.35.12447)^2 + (-173.02222)^2)^(1/2) = 852.85964 N angle of resultant = arctan(Fy/Fx) = arctan(835.12447/-173.02222) = 78.29. The answers in the back of the book say 853 N and 101.7 degrees. I have the resultant correct but not the angle. If I had both wrong, I wouldn't question it, but one right and one wrong makes me question it. What went wrong?