## Learning Journals - Section 1: Lesson Opener

# Flexing Our Bisectors

Lesson 11 of 14

## Objective: SWBAT use dynamic geometry software to construct a (segment) bisector and verify its properties. Students will understand how learning constructions helps them to understand the properties of geometric objects.

#### Lesson Opener

*5 min*

**Team Warm-up**

The Warm-Up prompt is a leading question: I ask students to consider the limitations of pencil-and-paper constructions, so that I can point out the advantages of dynamic geometry software.

This lesson opener follows our Team Warm-up routine, with students writing individual answers in their Learning Journals. I display the prompt using the Slideshow for the lesson.

**Goal-Setting**

Displaying the lesson Agenda and Learning Targets, I tell the class that today we will learn how to use dynamic geometry software to construct a bisector and investigate its properties. The software allows us to construct a figure, then move its vertices or change some of its measurements to see how this effects the figure.

The application we will be using is a freeware program called WinGeom.

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**Team Size-Up**

The lesson close follows our Team Size-Up routine. The Lesson Close prompt asks students to name some of the advantages of dynamic geometry software.

**Homework**

Homework Set 2 problem #28 gives students another chance to use constructions to examine the properties of bisectors. Problem #29 provides practice with vocabulary and geometric notation. In Problem #30, students follow instructions (written using geometric vocabulary and notation) to construct an equilateral triangle inscribed in a circle.

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- UNIT 1: Models and Constructions
- UNIT 2: Dimension and Structure
- UNIT 3: Congruence and Rigid Motions
- UNIT 4: Triangles and Congruence
- UNIT 5: Area Relationships
- UNIT 6: Scaling Up- Dilations, Similarity and Proportional Relationships
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- LESSON 1: Welcome to Geometry!
- LESSON 2: Preview and Goal-Setting
- LESSON 3: Mystery of the Nazca Lines
- LESSON 4: Cell Phone Towers
- LESSON 5: Cell Phone 9-1-1
- LESSON 6: Submarine Smart Phone
- LESSON 7: Reviewing Geometric Models
- LESSON 8: Introduction to Constructions
- LESSON 9: Going Halvesies
- LESSON 10: Inventory Testing
- LESSON 11: Flexing Our Bisectors
- LESSON 12: Finding Your Center
- LESSON 13: Reviewing Constructions
- LESSON 14: Models & Constructions Unit Quiz