Answer:
AD = 6
Step-by-step explanation:
If a radius is perpendicular to a chord, then it bisects the chord.
Here XB is the radius, AC is the chord. Given XB and AC are perpendicular to each other. Therefore, XB bisects AC at D.
So,
[tex]AD = \frac{1}{2} \times AC = \frac{1}{2} \times 12 = 6[/tex]
