Question 878193
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.
{{{3^2+(AP)^2=5^2}}}
{{{9+AP^2=25}}}
{{{AP^2=16}}}
{{{highlight(AP=BP=4)}}}
The chord described, which is AB, is {{{highlight(AP+BP=4+4=8)}}}