Properties of Similar Triangles

1.) Check the check boxes and see the relationship between the triangles. What do you observe?
2.) Move the verticles of the smaller triangle. Are your observations still the same?
3.) Make a conjecture about your observations.

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There is a discussion about similar triangles and their properties (part 1 and part 2) in my main blog, Mathematics and Multimedia.

Download GGB files

Constructing Similar Triangles

1.) Move the slider to the right to construct a triangle similar to triangle ABC.
2.) Using the tools on the toolbar to compare the measure of the interior angles, side lengths, and areas of the two triangles. What do you observe?

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3.) Move the vertices of triangle ABC. Do your observations still hold?
4.) Make conjectures based on your observations and prove your conjectures.

Download GGB file 

Reduction and Enlargement

This applet shows the enlargement/reduction of a triangle with scale factor k and center O.




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Here are several of the activities that the teacher/student can do:

• The teacher may hide some elements in the objects (using the check box), and let the students predict the position of the missing objects.
• The students may use the distance, area and angle tools to investigate the relationship between the two triangles. 

Click here to download applet.