# Understand the connections between proportional relationships, lines, and linear equations.

### Popular Tutorials in Understand the connections between proportional relationships, lines, and linear equations.

#### What are Similar Figures?

Looking at two figures that are the same shape and have the same angle measurements? You have similar figures! Learn all about it in this tutorial!

#### What's the Formula for Slope?

When you're dealing with linear equations, you may be asked to find the slope of a line. That's when knowing the slope formula really comes in handy! Learn the formula to find the slope of a line by watching this tutorial.

#### What Does the Slope of a Line Mean?

You can't learn about linear equations without learning about slope. The slope of a line is the steepness of the line. There are many ways to think about slope. Slope is the rise over the run, the change in 'y' over the change in 'x', or the gradient of a line. Check out this tutorial to learn about slope!

#### What's the Constant of Variation?

The constant of variation is the number that relates two variables that are directly proportional or inversely proportional to one another. But why is it called the constant of variation? This tutorial answers that question, so take a look!

#### What Does Direct Variation Look Like on a Graph?

Want to know what a direct variation looks like graphically? Basically, it's a straight line that goes through the origin. To get a better picture, check out this tutorial!

#### What Does Negative Slope Mean?

What does a negative slope mean? What does the graph of a negative slope look like? Find the answers to these questions by watching this tutorial!

#### What Does Positive Slope Mean?

What does a positive slope mean? What does the graph of a positive slope look like? Find the answers to these questions by watching this tutorial!

#### What Does 0 Slope Mean?

A zero slope is just the slope of a horizontal line! The y-coordinate never changes no matter what the x-coordinate is! In this tutorial, learn about the meaning of zero slope.

#### What Does Undefined Slope Mean?

An undefined slope (or an infinitely large slope) is the slope of a vertical line! The x-coordinate never changes no matter what the y-coordinate is! There is no run! In this tutorial, learn about the meaning of undefined slope.

#### What's Slope-Intercept Form of a Linear Equation?

When you're learning about linear equations, you're bound to run into the point-slope form of a line. This form is quite useful in creating an equation of a line if you're given the slope and a point on the line. Watch this tutorial, and learn about the point-slope form of a line!

#### What's the Direct Variation or Direct Proportionality Formula?

Ever heard of two things being directly proportional? Well, a good example is speed and distance. The bigger your speed, the farther you'll go over a given time period. So as one variable goes up, the other goes up too, and that's the idea of direct proportionality. But you can express direct proportionality using equations, and that's an important thing to do in algebra. See how to do that in the tutorial!

#### What is a Linear Equation?

If you're learning about graphs, you're bound to see a bunch of linear equations, so it's a good idea to understand what makes an equation a linear equation. This tutorial explains linear equations and shows you the difference between equations that are linear and ones that are not. Check it out!