This section is about the arc of a circle.
The length of an arc of a circle is expressed in linear unites
of measurement such as inches or centimeters. Below is a
picture of a circle arc showing the arc length in a circle.
Later on, we will discuss the formula for arc length in a
Measuring the arch length of a circle
Degrees are used to represent the measure of
an arc. A degree is a unit of measurement obtained by dividing
one complete revolution (circle) into 360 equal parts. Each
part is called a degree.
How many degrees does a circle have?
A circle has 360 degrees. This can be
assumed for all circles. The measure of a circle is 360
degrees. Therefore, the measure of a semi circle is 180
Definition of a major arc of a circle
A major arc of a circle is an arc with a
degree measure of greater than 180 degrees but less than 360
degrees (see picture of a circle above).
Definition of a minor arc of a circle
Likewise, the definition of a minor arc of a
circle is an arc with a degree measure of less than 180.