Extension: Parallel Lines and the Sum of the Angles

Author

Texas Instruments

Alignment

Standards Alignment

Textbook Alignment

Subject Area

Math: Geometry: Points, Lines and Angles

Math: Geometry: Triangles

Level

6-8

Activity Time

30 Minutes

Software

TI Connect™

TI Calculator

TI-84 series

Applications

Cabri™ Jr. for TI-83 Plus and TI-84 Plus

Other Materials

TI-Presenter™

LCD Projector
Two screens

Resource Types

Lessons

Report an Issue

Extension: Parallel Lines and the Sum of the Angles

Activity Overview

Students construct a line parallel to the base of a triangle and measure the angles formed. They use the construction to prove that the sum of the measures of the interior angles of a triangle is 180 degrees.

Before the Activity

Install the Cabri™: Jr. App on the students' graphing calculators using one of these two methods:

TI-Connect™, a TI Connectivity Cable, and the Unit-to-Unit Link Cable

TI-Navigator™ "send to class" feature

See the attached PDF file for detailed instructions for this activity

Print pages 1 - 4 from the attached PDF file for your class

During the Activity

Distribute the pages to the class.

Follow the Activity procedures:

Draw a line parallel to the base of a triangle through the top vertex

Measure the angles that are formed by the parallel line and the sides of the triangle

Measure the interior angles of the triangle

Use the figure to prove that the sum of the interior angles of any triangle is 180 degrees

After the Activity

Review student results:

As a class, discuss questions that appeared to be more challenging

Re-teach concepts as necessary

Download Files

Download All Files (ZIP)

Before the Activity Files

Teacher Notes PDF

Author

Texas Instruments

Alignment

Standards Alignment

Textbook Alignment

Subject Area

Math: Geometry: Points, Lines and Angles

Math: Geometry: Triangles

Level

6-8

Activity Time

30 Minutes

Software

TI Connect™

TI Calculator

TI-84 series

Applications

Cabri™ Jr. for TI-83 Plus and TI-84 Plus

Other Materials

TI-Presenter™

LCD Projector
Two screens

Resource Types

Lessons

Report an Issue

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Vernier EasyData,Vernier EasyLink and Vernier EasyTemp are registered trademarks of Vernier Science Education.

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Extension: Parallel Lines and the Sum of the Angles

Cabri™ Jr. for TI-83 Plus and TI-84 Plus

Extension: Parallel Lines and the Sum of the Angles

Before the Activity Files

Cabri™ Jr. for TI-83 Plus and TI-84 Plus

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