since this is high school math, i doubt we can get more sophisticated than the following idea. but then again, i don't remember much about high school--it was a blur

try graphing the vectors on a pair of axes. you should be able to use trig ratios to find the x and y co-ordinates of each.

let (a,b) be the coordinates of the first and (c,d) the coordinates of the second.

then you want the vector that terminates at (a - c, b - d). then you can describe that point in terms of its distance from the origin and the angle it makes with the positive x-axis