# Angles & intersecting lines

Contents
This topic continues our journey through the world of Euclid by helping us understand angles and how they can relate to each other.

## Angle basics & measurement

This tutorial will define what an angle is and help us think about how to measure them. If you're new to angles, this is a great place to start.

## Angle types

Explore the different types of angles

## Complementary & supplementary angles

In this tutorial we'll look at the most famous types of angle-pairs--complementary and supplementary angles. This aren't particularly deep concepts, but you'll find they do come in handy!

## Angles between intersecting and parallel lines

Welcome. I'd like to introduce you to Mr. Angle. Nice to meet you. So nice to meet you. This tutorial introduces us to angles. It includes how we measure them, how angles relate to each other and properties of angles created from various types of intersecting lines. Mr. Angle is actually far more fun than you might initially presume him to be.

## Angles with triangles & polygons

Do the angles in a triangle always add up to the same thing? Would I ask it if they didn't? What do we know about the angles of a triangle if two of the sides are congruent (an isosceles triangle) or all three are congruent (an equilateral)? This tutorial is the place to find out.

## Angles with polygons

Explore properties of angles in and arou polygons.

## Sal's old angle videos

These are some of the classic, original angle video that Sal had done way back when (like 2007). Other tutorials are more polished than this one, but this one has charm. Also not bad if you're looking for more examples of angles between intersected lines, transversals and parallel lines.