# How to demonstrate sin(π/6) = 1/2?

I'm trying to demonstrate:

$$\sin(π/6) = \sin(30º) = 1/2$$

Which property or assumption I should use to start?

• Use a equilateral triangle. Sep 10 '16 at 16:05
• it depends how you have defined the sine function Sep 10 '16 at 16:05
• I'll check, thank you. @Ana Sep 10 '16 at 16:06

Hint for other solution: $$1 = \sin(\pi/2) = \sin(3(\pi/6)) = \text{some polynomial}(\sin(\pi/6)).$$ (for the last $=$ apply some trigonometric formula)