Illuminations: Scale Factor

Scale Factor


A common misconception is that when the dimensions of an object are doubled, the area is doubled, too. But this is not true! Use this applet to investigate how changes in the scale factor influence the ratio of perimeters and the ratio of areas between two figures.

Instructions

 
The size of Rectangle A can be modified by dragging the red vertices in the upper left and lower right corners of the figure. The Scale Factor can be set to any integer value from 1 to 6. Rectangle B will correspondingly appear from 1 to 6 times as large as Rectangle A.

Exploration

 
How does the ratio between the perimeters change as the scale factor changes?

How does the ratio between the areas change as the scale factor changes?

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NCTM Resources

Navigating through Geometry in 6‑8

Lessons


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