Is an angle formed by two chords in a circle which have common endpoint?

Is a portion of a circumference of a circle?

  It is the longest chord of a circle.

A segment drawn from any point on the circle to the center.

  A secant is a line that contains a chord.                

A chord that contains the center of the circle is called diameter.

If a circle is divided into three equal arcs, each is a major arc.

   A circle has only a finite number of equal chords.

  Line segment joining the center to any point on the circle is a radius of the circle.