Investigating Scale Factors

Adapted from Walch EducationInvestigating Scale Factors

Key Concepts1.1.2: Investigating Scale Factors2The notation is as follows: Dk(x, y) = (kx, ky).

Multiply each coordinate of the figure by the scale factor when the center is at (0, 0).

Concepts, continued1.1.2: Investigating Scale Factors3The lengths of each side in a figure also are multiplied by the scale factor.

If you know the lengths of the preimage figure and the scale factor, you can calculate the lengths of the image by multiplying the preimage lengths by the scale factor.

The dilation is an enlargement if k > 1, a reduction if 0 < k < 1, and a congruency transformation if k = 1.Lets Practice1.1.2: Investigating Scale Factors4A triangle has vertices G (2, 3), H (6, 2), and J (0, 4). If the triangle is dilated by a scale factor of 0.5 through center C (0, 0), what are the image vertices? Draw the preimage and image on the coordinate plane.Step 11.1.2: Investigating Scale Factors5Start with one vertex and multiply each coordinate by the scale factor, k.Dk = (kx, ky)

Step 21.1.2: Investigating Scale Factors6Repeat the process with another vertex. Multiply each coordinate of the vertex by the scale factor.

Step 31.1.2: Investigating Scale Factors7Repeat the process for the last vertex. Multiply each coordinate of the vertex by the scale factor.

Step 41.1.2: Investigating Scale Factors8List the image vertices.

Step 51.1.2: Investigating Scale Factors9Draw the preimage and image on the coordinate plane.

Your turn.1.1.2: Investigating Scale Factors10What are the side lengths of with a scale factor of 2.5 given the preimage and image to the right and the information that DE = 1, EF = 9.2, and FD = 8.6?

Thanks for watching!Ms. Dambreville