# $\sin{18^\circ}$ value

The value of sine function for angle $18$ degrees is called sine of angle $18$ degrees.

It is represented as $\sin{18}^\circ$ in Sexagesimal system, $\sin{\Big(\dfrac{\pi}{18}\Big)}$ in Radian system and $\sin{20}^g$ in Centesimal system.

The value of sine of angle $18$ degrees in fraction.

$\sin{18}^\circ = \dfrac{\sqrt{5}-1}{4}$

The value of sine of angle $18$ degrees in decimal.

$\sin{18}^\circ = 0.309016994 \ldots$

### Proof

Now, learn how to derive the sine $18$ degrees value in fraction and decimal form by trigonometric and geometrical methods.