Download Segments and angles inside the circle:

Geometry
NAME:
NOTES: Circles – Arcs & Central Angles
PERIOD:
DATE:
Arcs & Central Angles of Circles
A circle has a total of 360°…
To understand angle relationships related to circles, the following terms are required:
Central Angle An angle with its vertex at the center of the circle.
Arc
An unbroken part of a circle…any two points on a circle are the endpoints of the
arc between them.
Like an angle, arc’s have a corresponding degree measure.
Minor arc
An arc measuring less than 180°.
Minor arcs are named using the arc’s endpoints with an arched “hat”… ex: AB
The measure of a minor arc is equal to the measure of its central angle. (mAB)
Major arc
An arc measuring more than 180°, but less than 360°.
Major arcs are named for the endpoints and a point between them… ex: ACB
The measure of a major arc is equal to 360° minus the measure of its minor arc.
Semicircle
An arc whose endpoints are on a diameter of the circle.
A semicircle also uses three letter notation.
A semicircle measures 180°.
Adjacent Arcs Two arcs in the same circle with exactly one point in common (an endpoint).
Intercepted Arc The arc formed by intersecting an angle with a circle (the arc “cut off” by an angle)
Use Circle Q to complete the following.
B●
1) Name two central angles.
2) Name four (4) minor arcs.
Q
●
A
3) Name four (4) major arcs.
4) Name two (2) semicircles.
●
D
5) Name two (2) minor arcs adjacent to AB.
6) Name two (2) major arcs adjacent to AB.
7) Name the arc intercepted by DQC.
8) If mAQD = 60°, then mAD = __________ and mABD = __________.
9) If mDBC = 220°, then mDC = __________ and mDQC = __________.
C