In the circle given below, let OA = 1 unit, OB = 13 unit and  PQ⊥OB. Then, the area of the triangle PQB (in square units) is

Consider the figure  Let PA = λ then AQ = λ  We know that   AP.AQ = AO.AB                        λ·λ     =  1 · 12      ( AB = 13-1 =12  )                            λ     = 2·3   Area of triangle PQB =  12 PQ.AB = 12·2λ·12  = 23 ·12 =243