A chord of a circle is a straight line segment that joins any two points on the circumference of the circle. The diameter of a circle is also considered a chord that passes through the center of the circle and is the longest chord of that specific circle. Some properties of chords of a circle include:
- Chords are equidistant from the center if and only if their lengths are equal.
- Equal chords are subtended by equal angles from the center of the circle.
- If the line extensions (secant lines) of chords AB and CD intersect at a point P, then their lengths satisfy AP·PB = CP·PD.
The perpendicular line passing through the midpoint of a chord is called sagitta.
