Lesson 9 of 14
Objective: SWBAT use straight-edge and compass to construct a (segment) bisector and verify its properties. Students will understand how geometric objects may be defined in terms of other objects and identified using geometric notation.
The Warm-Up prompt for the lesson asks students to recall the properties of bisectors.
Displaying the lesson Agenda and Learning Targets, I tell the class that today we will learn how to construct a bisector and to use constructions to investigate their properties.
Constucting a Bisector
Practice & Investigation
I ask students to get out their Guided Notes: Constructions/ Defining Geometric Objects. Now that we know what lines and circles are, we can define other objects--segments, rays, and arcs--with precision (MP6). We complete the final page of the notes: Defining Geometric Objects.
Displaying the guided notes with the help of an interactive whiteboard, I lead the class in completing the definitions and the examples. I encourage students to use straight-edge and compass to construct the diagrams, although this is not strictly necessary.
Homework Set 2 problem #23 asks students to practice some of the constructions they have just learned. Problem #24 reviews algebra concepts (slope). In addition, I assign Portfolio Problem 2- Placing a Call, which students should now be able to answer completely.