**Stretching and Shrinking**

**By Lily Cyran, Quinn Jones, and Kevin Hock**

Beginning

Today, we will explain to you many things you need to know when enlarging a figure such as how to enlarge, what a scale factor is, what changes did or did not occur when enlarging or shrinking an object, and how the original image is similar to the enlarged image. In our case, we decided to enlarge a house, cloud, sun, and a flower because that scene completes one that is seen when looking at a typical house. The enlarged figure is five times bigger than the original.

Enlarging a Figure

**ELEMENTS**

Scale Factor

Changes that Did Not Occur

Conclusion

This presentation is mainly about stretching and shrinking a figure along with other ideas that relate to the topic.

Changes that Did Not Occur

Changes That Occurred

When you have the original figure, you first need to understand it. You need to realize what the base, height, and area of the figure is. Once you know those, then you have to multiply the coordinates by however much you want the figure to be enlarged. For example, if you want the figure to be twice as large you multiply the coordinates by two. Then, you graph the new coordinates that show the enlarged figure. Make sure you label the X and Y axises along with the units on your graph. Also, be positive you include the numbers below the axises and that they are accurately spaced. Check that the graph has a title as well! That is how you enlarge a figure and put it on a graph.

Enlarging a Figure

The difference from the smaller figure to the larger, or vise versa, all relates when you introduce the scale factor. The scale factor is the number multiply to see how much the original figure grew or shrank. Once you see the new figure, that is called the image. You find the scale factor by dividing the base of the larger figure by the base of the smaller figure. Or, by dividing the corresponding sides. Another way you could find the scale factor is by simply looking at the figure’s side lengths and know what the scale factor is. Side lengths matter a lot when dealing with the scale factor.

Scale Factor

Changes occurred with the length of sides because the figure was enlarged five times, so the side lengths were as well. Also, the area changed because the side lengths were changed. As you know, you find the area of a shape by figuring out the side lengths. Our original coordinates are similar to the enlarged coordinates because they have congruent angles, proportioned sides, and are the same shape.

Changes that Occurred

Some changes that did not occur include the ratio of corresponding sides, size of angles, and the shape. The ratio of corresponding sides did not occur because even if you reduce the numbers, the ratio still has the same meaning. For example, if you reduced 9:6 to 3:2, they still have the same content. The size of angles would not change because that basically means that the degree of angles stays the same. In order for a figure to be defined as similar, then it has to have congruent angles. Therefore, the size of angles would not change. Lastly, the shape would not change because you are enlarging the figure, which means to proportionally make the figure bigger. Also, the figure has to have the same shape for it to be similar.

To sum everything up, now you know important details that have to do with enlarging a figure that include how to enlarge, what a scale factor is, what changes did or did not occur when enlarging or shrinking an object, and how the original figure is similar to the enlarged image.

Conclusion

STRETCHING AND SHRINKING

Vocacabulary

Corresponding Sides- Sides that are in the same place in different figures.

Scale Factor- The number used to multiply the lengths of a figure to stretch or shrink it.

Image- The figure that results from some transformation of a figure.

Ratio- A comparison between two different objects.

Similar- Having congruent angles, proportioned sides, and is the same shape.

Congruent- The exact same.

Enlarging

Thank you for listening to our presentation! We hope you all learned something new about stretching and shrinking.