A chord separates the circumference of a circle into two sections - the major arc and the minor arc. It also separates the area into two segments - the major segment and the minor segment.

In the diagram below, AB is the chord of a circle with centre O. OM is perpendicular to AB (meet at a right angle). Look at triangles OAM and OBM. The hypotenuses (OA and OB) are the same ...