Answer:
16
Step-by-step explanation:
We can see that Ar is the perpendicular bisector of chord BD. Since A is the center of the circle, AR is the radius of the circle, which is 10 (6+4)
Next, we can see that when we connect point A to point D, it is also a radius. Thus, AD is also equal to 10 as the radius of the circle remains the same.
Using Pythagoras theorem, a^2 + b^2 = c^2, we can make a right angled triangle of ACD.
AC = 6 = a
CD = ? = b
AD = 10 = c
10^2 = 6^2 + b^2
b^2 = 10^2 - 6^2 = 64
b = CD = 8
Now, since Ar is the perpendicular bisector of chord BD, BD = CD x 2
BD = 8 x 2 = <u>16</u>
Perpendicular lines have slopes that are inverse reciprocals of each other. That would give you the new slope in your equation. After that plug (6,2) into point slope form and solve to get your final equation.