Introduction
When two line meet at a 90 degree angle, they are called perpendicular lines. Perpendicular lines are all around us. For example, when two roads cross they often form perpendicular angles.
Look at the patterns in the brick work. There are many examples of perpendicular lines here.
In this lesson, we will learn how to define and label perpendicular lines. In addition, we will learn how to identify the slope of perpendicular line and write its equation.
Following successful completion of this lesson, students will be able to...
- Determine whether two lines are parallel given their equations or graphs
- Write the equation of a line in slope intercept given the lines are perpendicular and passing through a given point
Essential Questions
- What does the slope a line tells you about the line?
- How are parallel lines and perpendicular line different?
- What does the equation of a line tell you about graph of the line?
Enduring Understandings
- The slope of a linear equation represents a constant rate of change.
- Linear relationships can be defined on the coordinate plane.
- The characteristics of linear equations and their graphs are useful in solving real-world problems.
- Slope can be used to prove that two lines are parallel or perpendicular.
- Slope can be used to prove that two lines are parallel or perpendicular.
The above objectives correspond with the Alabama Course of Study: Geometry standard: 33.