Process What is the ratio of the corresponding sides of the blue triangle to the red triangle? The ratio of corresponding sides of a figure is called the scale factor. In this problem the scale factor is 2. This is an enlargement because the scale factor is greater than 1. From To __

Process What is the ratio of the corresponding sides of the red triangle to the blue triangle? The ratio of corresponding sides of a figure is called the scale factor. In this problem the scale factor is 1/2. This is a reduction because the scale factor is less than 1.. From To __ To

( x,y )( x’,y’) (0,0) (3,0) (0,3)(3,3) (0,0) (6,0) (6,6) (0,6) The above rectangle was dilated by a What are the coordinates of vertices of the new rectangle? (0,0), (6,0), (0,6) and (6,6) scale factor of 2. ( 2x,2y) (2*0, 2*0) (2*3, 2*0) (2*3, 2*3) (2*0, 2*3)

Triangle ABC was dilated to produce triangle A’B’C’. What scale factor was used to produce this dilation? FromTo xx’ Rate Scale Factor ( 2,0)(8,0) = 4

In the previous problem, We used the x –value of the ordered pairs on the x-axis. Predict what would happen if we used the y –value of the ordered pairs on the y-axis. FromTo yy’ Rate Scale Factor 28 (0,2) (0,8) The scale factor is the same.

Regular pentagon ABCDE is similar to regular pentagon MNOPQ. The scale factor is 2.5. What is the length of the sides of pentagon MNOPQ. Missing Sides and Angles 2 A B C D E ? M N OP Q

Scaling Up or Down Determine the scale factor used to go from figure A to figure B. A B A B A B 3. Scale factor ________ 2. Scale factor ________ 1. Scale factor ________

Scaling Up or Down Guided Practice Determine the scale factor used to go from figure A to figure B. A B A B A B 3. Scale factor ________ 2. Scale factor ________ 1. Scale factor ________