1. Module 5

1.11. Lesson 3

Mathematics 10-3 Module 5 Lesson 1

Module 5: Angles

 

Lesson 3: Bisecting Angles

 

Focus

 

This is a photo of Rogers Centre in Toronto showing an angle formed by first base, home plate, and third base divided into two angles of the same size. The common side of the two angles runs through second base.

© Gizmo/iStockphoto

 

The photograph is a panoramic view of Rogers Centre, formerly called the Toronto SkyDome. Rogers Centre is the home of the Toronto Blue Jays, baseball’s World Series winners in 1992 and 1993.

 

If you take a closer look at the photo’s centre, you will see the layout of the baseball diamond. The first and third baselines form the angle that determines whether a ball is hit fair or foul. Second base, the pitcher’s mound, and home plate split that angle into halves. What is the measure of each half of that large angle?

 

In this lesson you will explore the geometry of angles and the lines that bisect, or divide, the angles into halves.

 

Lesson Questions

 

In this lesson you will explore these questions:

  • What does it mean to bisect an angle?

  • How are different techniques used to bisect angles?

Assessment

 

You will complete the Lesson 3 Assignment Booklet for assessment. Download the Lesson 3 Assignment Booklet and save it in your course folder now. You will receive instructions on how to complete the Assignment Booklet later in the lesson. You will also be prompted to start working on the Unit 3 Project.

 

Remember to save all activities, including those that are not part of the Assignment Booklet, in your course folder.

 

Required Materials and Equipment

 

For this lesson you will need the following supplies:

  • a protractor

  • compasses

  • a square from a geometry set

  • several blank sheets of paper

  • a straightedge or ruler