Lesson 4

In Try This 4, you saw that dilations change the size of an object, but not the shape of the object. To determine the new coordinates after a dilation, each x-coordinate and each y-coordinate is multiplied by the same scale factor. This means a dilation by a factor of 5 will give an object with lengths 5 times the size of those in the original image.

 

To determine the new points, multiply each x-coordinate and each y-coordinate by 5.

 

The scale factor of a transformation can be determined by dividing a length on the new object by the corresponding length on the original object.

 

A dilation by a factor larger than 1 creates a larger shape. In the following example, the dimensions of the dilated triangle will all be 3 times the size of the dimensions of the original triangle.

 

 

A dilation by a factor smaller than 1 creates a smaller shape. In the following example, the dimensions of the dilated triangle are the size of the dimensions in the original triangle.

 

 

Self-Check 3