Here, centre is A (1,2), and Tangent at B (1,7) is x . 1 + y . 7 (x + 1) - 2 (y + 7) - 20 = 0 or y = 7 ... (i) Tangent at D (4,-2) is 3x - 4y - 20 = 0 ...(2) Solving (1) and (2), we get C is (16,7) Area ABCD = 2 (Area of Δ ABC) = 2 × 21 AB × BC AB × BC = 5 × 15 = 75 units
