Introduction

City roads are great examples of lines that are cut by a transversal.

Consider the city or town where you live. Sometimes there will be a road named Main Street. When the layout of the land will allow, many roads called "streets" are parallel while other roads known as "avenues" intersect the streets forming blocks. The intersections form angle relationships.

Lesson Objectives

Following successful completion of this lesson, students will be able to...

  • Find the measure of angles formed by two parallel lines and a transversal

Essential Questions

  • How can I prove that two lines are parallel or perpendicular using angle measurements?
  • How can I use theorems and postulates about lines and angles to solve problems?

Enduring Understandings

  • Perpendicular lines can be proven by the relationship of their slopes.
  • If we know the measure of one angle formed when a pair of parallel lines is cut by a transversal, then we can find the measures of the other angles.
  • You can use the measures of angles to prove that lines are parallel.
  • If we know the measure of one angle formed when a pair of parallel lines is cut by a transversal, then we can find the measures of the other angles.
  • You can use theorems and postulates about lines and angles to find unkonwn measurements.

The above objectives correspond with the Alabama Course of Study: Geometry standard: 30, 31, and 31a.