Trigonometry is a whole branch of mathematics and does not comprise only one formula!
There are many.
The general term is trigonometry. What specific formula you use depends on what other information you have.
The answer depends on what other information is available to you.
moivre's formula
The answer depends on what other information is available to you.
Trigonometry is the study of plane and spherical triangles. Plane trigonometry deals with 2 Dimensional triangles like the ones you would draw on a piece of paper. But, spherical trigonometry deals with circles and 3 Dimensional triangles. Plane trigonometry uses different numbers and equations than spherical trigonometry. There's plane trigonometry, where you work with triangles on a flat surface, then there's spherical trigonometry, where you work with triangles on a sphere.
Trigonometry is basically formula's to help you find out unknown sides and angles of a triangle. Surveying is measuring land. But as not all land is equal so these formula's are used to help.
Mechanics use trigonometry to find angles mostly used in body or chassis work.
It's best when you are doing construction work like on a work site :)
Bartholomaeus Pitiscus is best known for his book called Trigonometria which was first published in Heidelburg in 1595. It consists of work on plane and spherical trigonometry. The book had the first recorded mention of the word "trigonometry".
Using trigonometry. The Hypotenuse x The height