Radian

Most people who do mathematics or physics use radians, rather than degrees, because some kinds of calculations, mostly in trigonometry and calculus, are simpler when using radians rather than degrees. Thus, most calculations related to angular frequency (such as angular velocity) use radians per second.

People who look through a telescope or sniper scope often use milliradians to describe distances as seen through it.

1 radian is equal to about 57.3°. There are 2π radians (about 6.28 radians) in a full revolution.^[2] The formula for converting radians to degrees and vice versa is:^[3]

${\displaystyle 2\pi {\mbox{ rad}}=360^{\circ }}$ 

${\displaystyle 1{\mbox{ rad}}={\frac {360^{\circ }}{2\pi }}={\frac {180^{\circ }}{\pi }}\approx 57.29577951^{\circ }}$ 

or:

${\displaystyle 360^{\circ }=2\pi {\mbox{ rad}}}$ 

${\displaystyle 1^{\circ }={\frac {2\pi }{360}}{\mbox{ rad}}={\frac {\pi }{180}}{\mbox{ rad}}\approx 0.01745329{\mbox{ rad}}}$ 

we can also say that:

${\displaystyle x{\mbox{ rad}}=\left({\frac {180x}{\pi }}\right)^{\circ }}$ .

• Steradian
• Tau, the measure of a full circle in radian
• Unit circle

1. ↑ "List of Geometry and Trigonometry Symbols". Math Vault. 2020-04-17. Retrieved 2020-08-31.
2. ↑ "Radian - math word definition - Math Open Reference". www.mathopenref.com. Retrieved 2020-08-31.
3. ↑ Weisstein, Eric W. "Radian". mathworld.wolfram.com. Retrieved 2020-08-31.

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