Geo NOTES
CIRCLE:
Date: _____
the set of all points in a plane that are equidistant from a given point called the
center.
RADIUS:
a segment that has one endpoint at the center of the circle, and the other endpoint
on the circle. Radius = ½ diameter
DIAMETER:
a segment that passes through the center of the circle and has both endpoints
on the circle. Two radii = one diameter
CHORD:
a segment that connects two points on the circle.
CENTRAL ANGLE:
ARC:
an angle whose vertex is at the center of the circle.
part of the circle (like walking on the rim of the circle)
MINOR ARC: - part of a circle that measures less than 180 degrees.
- use two letters to name it
- the measure of a major arc = measure of its central angle
MAJOR ARC: - part of a circle that measures more than 180 degrees.
- use three letters to name it
SEMI-CIRCLE: ½ of a circle (180 degrees) – use three letters to name it!
ADJACENT ARCS:
-
- two arcs in the same circle that have exactly one point in common.
You can add the measures of adjacent arcs just as you can add the measures
of adjacent angles.
EB is a diameter.
AD and EC are diameters.
Find the value of x:
Find the value of x:
HOMEWORK: pgs. 688-689 # 1-26 (all)
 DRAW the circles on your paper for #9-24 and fill in the
missing measurements !!!!
 DO NOT WRITE in the book!!!