The radian is a unit of angles, similar to degrees.
We can describe how far something has moved around a circle or the separation of hands on a clock using radians.
Key Concepts
When converting between degrees and radians, we use the fact that a complete circle is 360° \(= 2\pi\) radians.
- 180° \(= \pi\) radians.
- 1° \( = {\pi \over180}\) radians
- 1 radian \(= {180 \over \pi}\)°
For angles of less than 0.2 radians (10°), we can say that \(\sin (\theta) \approx \theta\) and \(\tan (\theta) \approx \theta\) provided the angle is in radians. Try this for yourself - but ensure your calculator is in 'R' mode (not 'D').
MY PROGRESS
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