Concept

Sine

For an acute angle of a right triangle, the sine of is the ratio between the lengths of the opposite side and the hypotenuse.
Sides of a right triangle labeled
The sine of is written as

This trigonometric ratio states the ratio between the opposite side and the hypotenuse. It gives no indication about the lengths of the individual sides.
Right triangle with two vertices movable and the sine of one acute angle is computed while the measures change
It should be noted that for a given angle, when the opposite side and hypotenuse measurements change, if their ratio stays the same, then the sine, too, would stay the same.
Exercises