11. In the following diagram, OA = a, OB = b and OC = C . Points P, Q, R, and S are the mid-points of OA, AB, BC and CO respectively. Determine the following vectors in terms of a, b and d . A Q B a) PQ b) QR a b P R C C S 12. Vector a joins the x- and y-intercepts (tail at the x-intercept and head at the y-intercept) of the line 2x + 3y = 6. Determine a, as a quadrant bearing