If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: 8th grade (Illustrative Mathematics)>Unit 2

Lesson 1: Lesson 4: Dilations on a square grid

# Dilating shapes: shrinking by 1/2

Dilations are transformations that change the size of a shape and its distance from the center of dilation. When the center is the origin, we can change the distance by multiplying the x- and y-coordinates by the scale factor. That's how we find the new positions of the points after dilation. Created by Sal Khan.

## Want to join the conversation?

• can you have a scale factor of a negative?
• Yep, it will basically flip it. Say the point is 2 inches to the left of a line. If you dilate it by -3 now the point will be 6 inches to the right of it.
• What would happen if the dilation is not centered at the origin but at another point?
• u would dilate at that point, the point could act like the origin
• why is this taught in eight grade
• idk know but it is to hard for me
• I don't get how to dilate by a number with unknown lengths. How do you dilate exactly by the points?
• You count the distance of x and y of the old points and then dilate the ordered pair. Do this for all the points of the shape.
• What does this mean at ??
• it means that you're basically shrinking said triangle by 1/2
• This makes sense, and I am able to make the 1/2 calculations. But what scale factor is 1/3? That is a lot of decimals... How do you map that?
• I am confused on the whole thing
• bro me too
(1 vote)
• I still don't get how to move the shapes?