# Further Maths - Radians

> Source: https://ollybritton.com/notes/a-level/further-maths/topics/radians/ · Updated: 2020-10-14 · Tags: further-maths, school, a-level

##### How many radians in a full circle??
$$
2\pi
$$

##### How many radians in $360^{\circ}$??
$$
2\pi
$$

##### How many circles in a half turn??
$$
\pi
$$

##### What is $180^{\circ}$ in radians??
$$
\pi
$$

##### What is $\frac{\pi}{2}$ radians in degrees??
$$
90^{\circ}
$$

##### What is $90^{\circ}$ degrees in radians??
$$
\frac{\pi}{2}
$$

##### What is $\frac{\pi}{3}$ radians in degrees??
$$
60^{\circ}
$$

##### What is $60^{\circ}$ degrees in radians??
$$
\frac{\pi}{2}
$$

##### What is $\frac{\pi}{6} radians in radians??
$$
30^{\circ}
$$

##### What is $30^{\circ}$ degrees in radians??
$$
\frac{pi}{6}
$$

##### What is $\frac{pi}{4}$ radians in degrees??
$$
45^{\circ}
$$

##### What is $45^{\circ}$ degrees in radians??
$$
\frac{\pi}{4}
$$

##### What is the formula for arc length in terms of $r$ and $\theta$ for radians??
$$
r\theta
$$

##### What is the formula for the volume of a sector in terms of $r$ and $\theta$ for radians??
$$
\frac{1}{2}r^2\theta
$$

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