Trigonometry is the branch of mathematics that deals with the relationship between sides and angles of triangles. Trigonometry is an extremely useful branch of mathematics. Trigonometry was first applied to spheres and then was applied to planes. Physics relies on trigonometry as do many of the engineering fields. Surveyors have also used trigonometry for a very long time. Chemistry also uses trigonometry heavily. This unit will go through trigonometry and how trigonometry can be applied to real-world applications.