You can put this solution on YOUR website! Imagine a circle, center at O, and the endpoints of the chord are on the circle at points A and B. A segment extends from point O and is perpendicular to the chord segment AB. Call this intersection point, which is also a perpendicular bisector, point P.
That description is of two right triangles sharing a side, OP. These values are known:
OP = 3;
OA = OB = 5.
You want to find values for AP or BP, and knowing just one of them, you know that AB=2AP=2BP.
Pythagorean Right Triangle Equation will let you solve for AP or BP.
The chord described, which is AB, is