Radians · Year 12
In Year 12 you learn: radians.
Radians are another way of measuring angles, based on the radius: one radian is the angle that cuts off an arc equal in length to the radius. A full turn is 2π radians, and in radians the arc and sector formulas become much simpler.
Key facts
- π radians = 180°, so 2π = 360°.
- Degrees → radians: × (π)/180. Radians → degrees: × 180/π.
- Segment area = ½r²(θ − sin θ).