1. In the figure, D is the midpoint of OB and C is a point on AB such that AC : CB = 3 : 2. OC is produced to a point E such that OC : CE = 1 : k. Let OA = a and OB = b. (a) Express OC and DA in terms of a and b. B E (b) Express BE in terms of k, a and b. D (c) Given a = 3, b =4 and ZBOA = -, find a-b. 3 (d) Find the value of k such that BE is perpendicular to OE . O A