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)