What are radians?
- Radians are an alternative to degrees for measuring angles
- 1 radian is the angle in a sector of radius 1 and arc length 1
- A circle with radius 1 is called a unit circle
- Radians are normally quoted in terms of π
- 2π radians = 360°
- π radians = 180°
- The symbol for radians is c but it is more usual to see rad
- Often, when π is involved, no symbol is given as it is obvious it is in radians
- Whilst it is okay to omit the symbol for radians, you should never omit the symbol for degrees
- In the exam you should use radians unless otherwise indicated
How do I convert between radians and degrees?
- Use π c = 180° to convert between radians and degrees
- To convert from radians to degrees multiply by
- To convert from degrees to radians multiply by
- Some of the common conversions are:
- It is a good idea to remember some of these and use them to work out other conversions
- Your GDC will be able to work with both radians and degrees
Convert 43.8° to radians.
ii) Convert to degrees.