Hi!
There is a proven rule stating If two chords are congruent, then they are the same distance from the center of the circle.
In this case, the two chords are JR and OE. They are congruent, both being 3.8 units long. Therefore, they are both the same distance from M, the center.
Since both MA and ML intersect the chords JR and OE (respectively), at right angles, and the chords are congruent, then that means ML is congruent to MA.
Hope this helped!