# Unit circle

### Unit circle

###### Basic concepts:

- Use sine ratio to calculate angles and side (Sin = $\frac{o}{h}$ )
- Use cosine ratio to calculate angles and side (Cos = $\frac{a}{h}$ )
- Use tangent ratio to calculate angles and side (Tan = $\frac{o}{a}$ )
- Find the exact value of trigonometric ratios

###### Related concepts:

- Sine graph: y = sin x
- Cosine graph: y = cos x
- Tangent graph: y = tan x