Equation of perpendicular bisector of AB is x−2y=−4 Equation of perpendicular bisector of AC is x+y=5 Point B is the image of A in line x−2y+4=0 which is obtained as B(
−13
5
,
26
5
) Similarly vertex C:(7,4) Equation of line BC:x+8y=39 So, p=8 AC=√(7−1)2+(4+2)2=6√2 Area of triangle ABC=32.4