MP3 Lesson 1 Circles and Arcs

Circle

•The set of all
points in a plane
that are
equidistant from a
given point.

Center

•The given point in a circle where all
set of points on the circle are
equidistant from that point.

•Circle is named by the center.

Diameter

•A segment that contains the center of
a circle and whose endpoints are on
the circle.

Radius

•A segment that has one endpoint at the
center of a circle and the other endpoint
on the circle.

Central
Angle

•An angle whose vertex
is the center of a circle
and is formed by its
endpoints.

Arc

•Part of the
circumference
(curve/edge) of a circle.

This Photo by Unknown Author is licensed under CC BY-SA

Identifying and

Naming Arcs

•Minor Arc - An arc that is less than 180
degrees, named by its endpoints

•Major Arc - An arc that is larger than
180 degrees, Named by at LEAST 3
points, including its endpoints.

•Semicircle - A half of a circle, an arc that
measures exactly 180 degrees, Named
by its endpoints and a point on the arc.