sin Θ = opposite / hypotenuse
cos Θ = adjacent / hypotenuse
tan Θ = opposite / adjacent
sin x = 1/2 ⇒⇒ opposite is 1 ; hypotenuse is 2
cos x = ? / 2 ⇒ ? = √3 value of adjacent
tan x = 1 / ?
This is the 30 - 60 - 90 triangle.
sin 30 = 0.50
cos 30 = 0.866
tan 30 = 0.577