Dilation

Author

Jean-Marie Laborde and Frank Bellemain

Alignment

Standards Alignment

Textbook Alignment

Subject Area

Math: Geometry: Triangles

Level

9-12

Activity Time

20 Minutes

Resource Types

Lessons

Report an Issue

Dilation

Activity Overview

Students use the Cabri Geometry II Plus software to investigate the geometric property of dilation. They vary the scale factor and examine the effect on the dilation of a triangle.

Before the Activity

Download the Cabri Geometry™ software on the computer

See the attached FIG file for details of this activity

During the Activity

Follow the Activity procedure:

Move Point K along the line

Note that for positive values of K, the triangle maintains its shape, but changes its size with respect to point O

Note that for K = 1, the two triangles coincide

Note that for K = 0, the dilated triangle coincides with point O

Observe that for negative values of the scale factor K, the dilated image gets inverted, and increases in size as the K value decreases

Understand that at K = 0.50, the sides of the dilated triangle will be half the length of sides of the original triangle, while the angles remain same

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

CabriGeo_II_Plus_Act05.fig

Author

Jean-Marie Laborde and Frank Bellemain

Alignment

Standards Alignment

Textbook Alignment

Subject Area

Math: Geometry: Triangles

Level

9-12

Activity Time

20 Minutes

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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Dilation

Dilation

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