Definition and Equation of a Circle

• The set of all Points P having the same distance from the center C

• A closed figure made up of all those points in a plane that are at the same distance from a fixed point

• The set of all Points P having the same distance from the center C

• A closed figure made up of all those points in a plane that are at the same distance from a fixed point

Circle

• Point C is called

• Also called fixed point

Center of the Circle

Common distance from the Center

Radius

A chord passing through the center of a circle

Diameter

A line segment joining two points on a circle

Chord

A line intersects two points on a curve

Secant Line

• A line that touches a curve at a point

• A line perpendicular to the center of a circle

Tangent Line

• Perimeter of a circle

Circumference