Question 1110559
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Triangle AOB is isosceles, because AO and OB are radii of the circle.<br>
Let C be the point on AB such that OC is the perpendicular bisector of AB.<br>
Then triangles AOC and BOC are 30-60-90 right triangles, with OC the short leg.<br>
That means OC=6; then AC = BC = 6*sqrt(3), so AB = 12*sqrt(3).