The original worked lessons remain the main explanations. Use these focused reminders to check the conditions before you start.
Radians, degrees and complete rotations
Convert both ways between degrees and radians.
Use the radian definition and distinguish minor from reflex angles.
Retain full turns for distance, but reduce signed rotations for final direction.
\(180^\circ=\pi\) rad and \(\displaystyle \theta=\frac{s}{r}\) when both lengths use the same unit. A full turn is \(2\pi\) rad. A swept angle may exceed one turn; final direction and total travel are different quantities.