Unit 2 Lesson 7
In Unit 2 Lesson 7, we learned about 2 more transformations :
- Rotation - Where you turn a figure around center point. You always rotate counter-clockwise unless told otherwise. For rotating about the origin: 90° change the point from (x, y) to (-y, x), for a 180° change the point from (x, y) to (-x, -y), for a 270° change the point from (x, y) to (y, -x)
- Dilation - Where you change the size of a figure by a constant scale factor. For dilating about the origin, just multiply the points by the scale factor. If it is around another points, multiply the distance from each point to the center by the scale factor.
A rotation is an isometry, but a dilation isn't one because the size of the figure changes.