# Kabulongagirls/Trigonometry/Introduction

From WikiEducator

**Trigonometry** (from Greek *Τριγωνομετρία* "tri = three" + "gon = angle" + "metr[y] = to measure") is a branch of mathematics that deals with triangles, particularly those plane triangles in which one angle has 90 degrees (**right triangles**). It also deals with relationships between the sides and the angles of triangles and with the functions which describe those relationships.