From the figure shown,
Radius=OA=10cm.
AB is the chord drawn with the length=16 cm.
We know,
perpendicular drawn from the centre of the circle to the chord ,bisects the chord
hence, C is the midpoint of AB.
Therefore,
AC=AB2=162=8
So using Pythagorean Theorem:
OA2=OC2+AC2
102=OC2+82
100=OC2+64
OC2=36
OC=6cm