Transformation Geometry Dilations What is a Dilation Dilation

Transformation Geometry Dilations

What is a Dilation? ¡ Dilation is a transformation that produces a figure similar to the original by proportionally shrinking or stretching the figure.

Proportionally Let’s take a look… And, of course, increasing the ¡circle When a figure is dilated, it must be proportionally largeraor smaller increases the So, we always have circle with a diameter. than thediameter. original. We are just certain changing the size or scale. Decreasing the We have a circle size of the with a certain circle diameter. decreases the diameter. ¡ Same shape, Different scale.

Which of these are dilations? ? A C HINT: SAME SHAPE, DIFFERENT SIZE D B

Scale Factor and Center of Dilation When we describe dilations we use the terms scale factor and center of dilation. Here we have Igor. He is 3 feet ¡ Scale factor ¡ Center of Dilation tall and the greatest width across his body is 2 feet. He wishes he were 6 feet tall with a width of 4 feet. His center of dilation would be where the He wishes he were larger by a length and greatest width of his body scale factor of 2. intersect.

Scale Factor If the scale factor is larger than 1, the figure is enlarged. ¡ If the scale factor is between 1 and 0, the figure is reduced in size. ¡ Scale factor > 1 0 < Scale Factor < 1

Are the following enlarged or reduced? ? C A Scale factor of 1. 5 D B Scale factor of 0. 75 Scale factor of 1/5 Scale factor of 3

The Object and the Image B’ ¡ ¡ ¡ The original figure is called the pre-image and the new figure is called the image. The pre-image is labeled with letters. The image may be labeled with the same letters followed by the prime symbol. Image C’ A’ B Pre-Image A C

Dilations Used Everyday

Remember ¡ ¡ Dilations are enlargements or reductions. What are some things that you would not mind dilating to make larger or smaller?