Answer:
x=22
Explanation:
In the top lines, it is given they are perpendicular, in the bottom case, you don't know that. However, it is given that the line from the center intersects halfway the chord (I looked that up). By definition that means that these lines are also perpendicular. Since the line from the center is 12 units in both cases, the top chord must be the same size as the bottom chord.
x seems to denote the total length, so that's twice 11, x=22