Trigonometry – Radians

In this lesson we will learn:

• What's a radian? Discover another way to measure angles.
• Radians and degrees: How to switch back and forth between units for angles
• Lengths of circular arcs: A formula for arc length in terms of radius and angle
• Sectors: Learn what a sector is, and a formula for finding its area

Degrees to radians: x degrees = (Pi/180 time x) radians
Radians to degrees: x radians = (180/Pi time x) degrees
Circular arc is part of a circle’s circumference between two radii.
Sector is part of a circle between two radii.

Trigonometry – Radians | What's a radian? | Radians and degrees: 

Trigonometry – Radians | Lengths of circular arcs | Sectors: