Trigonometry Terminology

Trigonometry

The study of triangles and their angles and side lengths

Sine

The ratio of the leg opposite the angle to the hypotenuse

Cosine

The ratio of the leg adjacent to the angle to the hypotenuse

Tangent

The ratio of the leg opposite the angle to leg adjacent to the angle

Angle of elevation

Formed by an observer’s sight line and a horizontal line when looking up at something

Angle of depression

Formed by the observer’s sight line and a horizontal line when looking down at something

Law of Sines

(sinA/a)=(sinB/b)=(sinC/c)

Law of Cosines

a²=b²+c²-2bc(cosA)

b²=a²+c²-2ac(cosB)

c²=a²+b²-2ab(cosC)