Module 1: Geometry – Introduction to triangles

Geometry is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space. A mathematician who works in the field of geometry is called a geometer.

A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices A, B, and C is denoted . In Euclidean geometry any three points, when non-collinear, determine a unique triangle and simultaneously, a unique plane (i.e. a two-dimensional Euclidean space).

Triangles are basic geometrical shapes that we meet everywhere around us.

They tell us what to do, or help us to do things right. They intrigue or delight us, or even give us shelter. They feature in craft and design. Sometimes our eyes perceive a 2-D triangular outline on what is really a 3-D object.

In the following units you will learn about different ways of naming triangles. Mathematics) geometry a three-sided polygon that can be classified by angle, as in an acute triangle, or by side, as in an equilateral triangle. Sum of interior angles: 180°; area: base × height. 2. any object shaped like a triangle.