Sine
In a right triangle, the ratio of the side opposite an angle to the hypotenuse.
Sine is one of the three primary trig functions: sin θ = opposite / hypotenuse. Extended to the unit circle, sin θ is the y-coordinate of the point reached after rotating θ radians from the positive x-axis. It is periodic with period 2π and takes values in [−1, 1].
Formula
sin θ = opposite / hypotenuse