Definition: Trigonometry is a branch of mathematics which concerns itself with the relationships between lengths, angles, and triangles. It deals with all sorts of measurements in terms of angles, such as the angle measure of a line segment or the area and volume of shapes formed by these lengths. The term 'trigonom' refers to the angles within this broader topic. In trigonometry, 'angles' are not just fixed points; rather, they can be any point on a line (the sides of the triangle), or they can form a polygon in three-dimensional space (a shape formed by the lengths of its edges and vertices). The term 'trigonom' is used to refer specifically to angles that are measured as parts of triangles. There are many different types of trigonometry, each with its own specific rules. Some examples include right angle triangle trigonometry, which deals with acute angles; circular (or circular) angle trigonometry, which deals with angles measuring more than 90 degrees; and spherical (or spherical) angle trigonometry, which is used for calculations in celestial mechanics. Understanding trigonometry can help us to solve problems involving triangles, such as finding the length of a side when we know the other two sides or the measures of the interior angles. It also has practical applications in navigation and engineering, where it is used to calculate distances and slopes. Overall, trigonometry is an important part of mathematics and science that deals with relationships between lengths, angles, and shapes.