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>
