# Mathematics I (Math 1132)

Durham College, Mathematics
Free
• 42 lessons
• 0 quizzes
• 10 week duration
• ##### Measurements

An introduction to numerical computation. Emphasis is placed on scientific and engineering notation, the rule of significant figures, and converting between SI and Imperial units.

• ##### Fractions, Percentage, Ratios and Proportion

Emphasis here is placed on understanding fractions, percent, and using ratios to compare quantities and set up proportions to solve problems.

• ##### Geometry

This unit focuses on analyzing and understand the characteristics of various shapes, both 2D and 3D.

## Mathematics I (Math 1132)

### Calculate the interior angles of polygons

A polygon is a plane figure formed by three or more line segments. The points where the sides meet are called vertices, and sum of the lengths of a polygon’s sides is its perimeter. If all of the sides and angles of a polygon are equal, it is called a regular polygon. In the diagram below, both shapes are hexagons, but the one on your left is a regular, while the one on the right is irregular.  Equal sides or angles are illustrated with daggers |.

The simplest of all polygons is a triangle. It has three sides and the total sum of its interior angles is 180°. In this section, you’ll learn how to calculate the sum of the interior angles of any polygon. The formula that’s used to calculated the total sum is:

Sum of Angles

$S=180°\left(n–2\right)\phantom{\rule{0ex}{0ex}}$

Where represents the total sum and n represents the number of sides. Let’s take a look at four different examples in increasing difficulty.