Chapter 2 Justification and Similarity 2.2 Students will be able to perform dilations and determine common qualities of the two figures. Students will identity the properties of similar figures.

2.21 Dilations Make a point in the lower left corner of the paper Draw a polygon to the right and up from the points Using the 2 rubber bands Place one end on the point Stretch rubber band so knot connecting the rubber bands is on the figure Put pencil inside loop of second rubber band and draw on the paper as your trace the shape with the knot Repeat with 2 rubber bands

Dilation Making a figure grow or shrink by a scale factor How to make a dilation Write coordinates of all the points Multiply all the points by the scale factor Plot all new coordinates and connect Or From point of dilation draw a ray through all points in the object Do scale factor to the length of the segment from point to vertices

Dilation Finding the scale factor and point of dilation Write down ordered pairs of original and new Take x value of new and divide by x value of original this will give you scale factor Draw a line through corresponding vertices and see where they intersect to get point of dilation

Similar Polygons Shame shape but different size Work through 2-48 What did you notice Work through 2-49 How can we determine if figures are similar All corresponding angles are congruent, but sizes of sides are different All corresponding sides use the same scale factor or same proportion

Similar Polygons To prove them similar AAA SSS SAS ASA If corresponding angles are congruent and corresponding sides are proportions Proof is written similar other than proving sides proportional

Homework Worksheet on Dilations Worksheet on similar polygons