Parts of a Circle
Center - the point in which all points on the circle are equidistant from
Radius - The line segment drawn from the center to a point on the circle.
Diameter - The line segment that is drawn through the center with endpoints on the circle.
Chord - A line segment with endpoints on the circle. The diameter is a special chord.
Tangent - a line that intersects the circle at only one point called the point of tangency.
Secant - a line that intersects the circle at exactly two points.