1. The problem statement, all variables and given/known data Find P-Q (P=11.5 kN, Q=12.5kN) 2. Relevant equations x-component = cos(angle)*force y-component = sin(angle)*force Pythagorean Theorem (to find resultant magnitude): c2 = a2 + b2 arctan (y-component / x-component) : to find angle of resultant 3. The attempt at a solution The answers for this problem are given to me in my book: magnitude = 14.63 kN @ 160.6° However, I am having trouble getting the direction. I first solved for the x and y components of P: x-component = cos(75)*11.5 = 2.97642 y-component = sin(75)*11.5 = 11.1081 Then I replaced Q with -Q and solved for the x and y components: x-component = cos(-30)*12.5 = 10.8253 y-component = sin(-30)*12.5 = -6.25 I then solved for the magnitude by adding the x-components and y -components, and then used Pythagorean theorem: x-component = 10.8253+2.97642 = 13.8017 y-component =-6.25 + 11.1081 = 4.8581 √(13.8017)2 + (4.8581)2 ≈ 14.63 kN (correct) Then I solve for the arctan of the components: arctan (4.8581 / 13.8017) ≈ 19.3917 My confusion arises here, since the book states that the angle is 160.6° which places the resultant in the second quadrant...however how can this be if the x and y components of my resultant are both positive, which suggests that it is in the first quadrant? If I subtract this from 180, I do get 160.608 which is the answer, but it doesn't make sense to me why I would do that?