radius: The distance from the center to the circle.
chord: A chord is defined as a line segment starting at one point on the circle and ending at another point on the circle.
diameter: A chord that goes through the center of the circle is called the diameter of the circle.
secant: A secant is a line that cuts through the circle and continues infinitely in both directions.
A tangent line is defined as a line that touches the circle at exactly one point. This point is called the point of tangency.
inscribed polygon: A convex polygon whose vertices all touch a circle is said to be an inscribed polygon.
circumscribed polygon: A convex polygon whose sides all touch a circle is said to be a circumscribed polygon.
Concentric circles are circles of different radii that share the same center point.
arc: A part or portion of a circle.
minor arc: An arc that is less than 180 degrees or half of the circle.
semi-circle: An arc that is exactly 180 degrees or half of the circle.
major arc: An arc that is more than 180 degrees or half of the circle.