Angle
Geometry shape formed by two rays (initial and ending sides of the angle) that share a common endpoint called the vertex. You may name an angle using the vertex, or a point in each ray and the vertex label in the center.

Cosine
Ratio determined by the hypotenuse in a right triangle and a side adjacent to a reference angle.

Hypotenuse
The side opposite the right angle in a right triangle

Ratio
A quotient of 2 numbers

Sine
Ratio of the length of the opposite side to a reference angle in a right triangle and the hypotenuse. Opposite/hypotenuse.

Tangent
The ratio of the length of the opposite side of a reference angle to the adjacent side to the same angle. Opposite over adjacent.