1. Arcs, Sectors & Segments

2. Radian Measure Degrees Radians Radians Degrees
The degree system is based on dividing a circle into 360 equal sectors, the measure of each being “one degree”
The radian system is based on the relationship between the radius and the arc length of a sector.
Therefore: measure of an angle in radians = ___________________
Angle measure (in radians) in a circle:
Converting from Degrees to Radians and from Radians to Degrees
Degrees Radians
Radians Degrees
Angle in Degrees
Π .
180
Angle in Radians
Angle in Radians
180 Π
Angle in Degrees

3. Arc Length Recall: RADIAN MEASURE ARC LENGTH
Radian Definition: One radian is defined as the size of an angle needed to cut off an arc of the same length as the radius
ARC LENGTH
Arc: part of the circumference of a circle.

4. Area of a Sector Sector: Perimeter of a Sector: Area of a Sector:
a 2D shape bound by 2 radii and the included arc of a circle
the area of a sector is a fraction of the area of a whole circle
Perimeter of a Sector:
Area of a Sector:

5. Examples

6. Example

7. Examples

8. Example