Trigonometric Ratios

Sine (sin), Cosine (cos), Tangent (tan)

The sine of an angle is the ratio of the length of the opposite side to the length of the hypotenuse: $$\text{sin } A = \frac{Opposite}{Hypotenuse}$$ .

The cosine of an angle is the ratio of the length of the adjacent side to the length of the hypotenuse: $$\text{cos } A = \frac{Adjacent}{Hypotenuse}$$ .

The tangent of an angle is the ratio of the length of the opposite side to the length of the adjacent side: $$\text{tan } A = \frac{Opposite}{Adjacent}$$ .

A right triangle.

The side opposite to angle θ.

The side next to angle θ that is not the hypotenuse.

The hypotenuse is the longest side of the triangle, opposite the right angle.

SOH-CAH-TOA, which stands for: Sine = Opposite/Hypotenuse, Cosine = Adjacent/Hypotenuse, Tangent = Opposite/Adjacent.

Angle A is 30 degrees (or π/6 radians).