Ответ на вопрос: 1. OAB is a triangle. A, B and C lie on a straight line, and P, Q and C lie on a straight line. P is the midpoint of OA, and Q is the midpoint of PC. OQ:QB = 3:1. OA=4 a and OB=5 b. (a) Find, in terms of a and b, the simplest form of (i) AB, (ii) OB, (iii) PO. (b) Using vectors, find the ratio AB:BC.