1. The problem statement, all variables and given/known data 2. Relevant equations x^2 + y^2 = r^2 3. The attempt at a solution I understand everything, but the last segment. What vector B when added to vector A, gives a resultant vector with no x component and a negative y component 3.34 units in length? So 3.34 = Sqr Root [(0^2) + (y^2)] You get 3.34 again, and because it states the y component should be negative, I plugged in -3.34, but alas, it's wrong. -.- Ignore the 2.12 that I plugged in on the screenshot, I was just trying different ways of working this out.