Mathematics for IGCSE & O level - Circle Theorems (Section 1 - No. 7)
If a line drawn from the center of a circle bisects a chord, what does that line do to the chord?
It's parallel to the chord.
It's the same length as the chord.
It's perpendicular to the chord.
It doesn't affect the chord's length.
Explication
The line is perpendicular to the chord.