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Similarity

Similarity

Author: Alex G
Description:

After you complete this packet you should be able to:
* Find missing side lengths in a pair of similar figures
* Find missing angle measurements in a pair of similar figures
* Use the notation for similarity of figures
* Find the scale factore between a pair of similar figures.

This packet covers vocabulary and concepts of similarity in a slide show format.

It also completes three examples of types common in geometry lessons about similarity.

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Tutorial

Similarity Concepts and Vocabulary

All similarity all the time.

First Example: Finding Missing Side Lengths of Similar Shapes

The video below works through this example of finding missing side lengths of similar triangles.

First Example: Steps

The steps I used to solve example one are below, in case you'd like to try it before you watch the video.  There is more than one way to attack this problem, however, so your method may be different from mine and still be correct.

Step One:  Write the similarity statement, making sure corresponding vertices are in the same position.
Step Two:  Write proportionality statement for the sides of the triangles.
Step Three:  Use WY to find XY
Step Four:  Use proportions to find WX

Find Missing Side Lengths of Similar Shapes

Second Example: Finding Scale Factor Between Similar Shapes

Example 2

Find Scale Factor Between Similar Shapes

Finds the scale factor given the dimensions of circles.

Third Example: Similarity in Art

Source: The Mona Lisa was painted by Leonardo Da Vinci in the early 1500's. This copy of it is in the public domain.

Determine Whether Figures are Similar

This example from the art world demonstrates how you can show through proportions whether two rectangles are similar.