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45. (a) Let P be a point not on the line L that passes through the points Q and R. Show that the distance d from the point P to the line L is a X b d = a where a = OR and b = QP. (b) Use the formula in part (a) to find the distance from the point P(1, 1, 1) to the line through Q(0, 6, 8) and R(- 1, 4, 7 )