Arc of Circle

Arc of a Circle

Minor & Major arcs

An arc is a part or a portion of a circle.

Diagram of Arc

You can think of the intercepted arc as the crust in a piece pizza.

intercepted arc as pizza crust

Intercepted Arc

An intercepted arc is created when segments (chords, secants, etc..) intersect a part of the circle. These segments in effect 'intercept' parts of the circle. The picture below shows examples of intercepted arcs.

Note: The examples below use chords to create the intercepted arc. However, tangents, secants can also create intercepted arcs.

picture of inercepted arcs

Arcs are grouped into two descriptive categories:

  1. minor arc
  2. major arc

In the circle below, there is both a major arc and a minor arc. Look at the circle and try to figure out how you would divide it into a portion that is 'major' and a portion that is 'minor'.

Arcs
HN is Minor Arc

Identify the major and minor arcs in the circle below.

  1. minor arc
  2. major arc

In the circle below, there is both a major arc and a minor arc. Look at the circle and try to figure out how you would divide it into a portion that is 'major' and a portion that is 'minor'.

Pitcure of Arc
Which is major arc

The measure of an arc = the measure of its central angle.

Therefore the measure of Measure of Arc AC = 85.

The measure of Measure of Arc ABC = 360° − 85° = 275°.

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