SOL Objective(s):
7.8 The student, given a polygon in the coordinate plane, will represent transformations (reflections, dilations, rotations, and translations) by graphing in the coordinate plane.
Khan Phrases:Dilations

The Basics and Background Information
• A rotation of a geometric figure is a turn of the figure around a fixed point. The point may or may not be on the figure. The fixed point is called the center of
rotation.
• A translation of a geometric figure is a slide of the figure in which all the points on the figure move the same distance in the same direction.
• A reflection is a transformation that reflects a figure across a line in the plane.
• A dilation of a geometric figure is a transformation that changes the size of a figure by scale factor to create a similar figure.
• The image of a polygon is the resulting polygon after the transformation. The preimage is the polygon before the transformation.
• A transformation of preimage point A can be denoted as the image A′ (read as “ prime”.
rotation.
• A translation of a geometric figure is a slide of the figure in which all the points on the figure move the same distance in the same direction.
• A reflection is a transformation that reflects a figure across a line in the plane.
• A dilation of a geometric figure is a transformation that changes the size of a figure by scale factor to create a similar figure.
• The image of a polygon is the resulting polygon after the transformation. The preimage is the polygon before the transformation.
• A transformation of preimage point A can be denoted as the image A′ (read as “ prime”.
Essential Knowledge and Skills
The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to...
•
•
Dilation of Objects on the Coordinate PlaneThis explains and models dilation and scale factor with the origin as the center and when the center of dilation is not the origin. For now, students only need to be able to dilate where the origin is the center of dilation  the first part of the video where the coordinates are simply multiplied by the scale factor.

