## Key Concepts

**Find the slope from a graph**

- Locate two points on the line whose coordinates are integers.
- Starting with the point on the left, sketch a right triangle, going from the first point to the second point.
- Count the rise and the run on the legs of the triangle.
- Take the ratio of rise to run to find the slope, [latex]m={\Large\frac{\text{rise}}{\text{run}}}[/latex]

**Slope of a Horizontal Line**- The slope of a horizontal line, [latex]y=b[/latex] , is [latex]0[/latex].

**Slope of a Vertical Line**- The slope of a vertical line, [latex]x=a[/latex] , is undefined.

**Slope Formula**- The slope of the line between two points [latex]\left({x}_{1},{y}_{1}\right)[/latex] and [latex]\left({x}_{2},{y}_{2}\right)[/latex] is [latex]m={\Large\frac{{y}_{2}-{y}_{1}}{{x}_{2}-{x}_{1}}}[/latex]

**Graph a line given a point and a slope.**- Plot the given point.
- Use the slope formula to identify the rise and the run.
- Starting at the given point, count out the rise and run to mark the second point.
- Connect the points with a line.

## Glossary

- slope of a line
- The slope of a line is [latex]m={\Large\frac{\text{rise}}{\text{run}}}[/latex] . The rise measures the vertical change and the run measures the horizontal change.