Find the sum of the following four vectors ((a) and (b) for x and y components respectively), and as (c) a magnitude and (d) an angle relative to +x (including sign plus or minus). P: 12.0 m, at 18.0 counterclockwise from +x Q: 20.0 m, at 7.90 counterclockwise from +y R: 14.0 m, at 16.0 clockwise from -y S: 6.20 m, at 43.0 counterclockwise from -y