OpenSAT

A chord of a circle divides the circle into two segments. The line segment drawn from the center of the circle to the midpoint of the chord is perpendicular to the chord. This line segment also bisects the chord. Since the diameter is 12 units, the radius is 6 units. A right triangle is formed by the radius, the line segment drawn from the center of the circle to the midpoint of the chord, and half the length of the chord. This right triangle is a 30-60-90 triangle, as the hypotenuse is twice the length of the shorter leg. The shorter leg of this triangle is 3 units, and the longer leg, which is the distance from the center of the circle to the chord, is units.