2. DILATIONS Transformations – Day 4

3. Warm Up Suppose point A(3, -4) is translated to point A’(5, -5). Write a rule (x, y)  (__, __) that describes this translation. Suppose point B(-2, 6) is rotated to Point B’(6, 2). Write a rule (x, y)  (_, _) that describes this rotation. QUIZ TODAY! 10 minutes End

4. Dilation Definition: A Dilation is a transformation that resizes a figure. It can get bigger or smaller but is still the same shape. Does a dilation have the property of isometry?

5. All Dilations have a scale factor Definition: A Scale Factor is the factor by which a figure has changed in size. Example: A scale factor of 3 makes a figure three times bigger. Example: A scale factor of ½ makes a figure ½ the size

6. http://www.mathopenref.com/dilate.html

7. What is the difference between an enlargement and a reduction? The dilation is an enlargement if the scale factor is greater than 1. enlargement The dilation is a reduction if the scale factor is between 0 and 1 reduction

8. How do you go from A to A’ Does that work for B to B’ and C to C’? A=(1,3) A’=(2,6) B C’ C B’

9. General Rule for Dilation Dilation by scale factor c (x, y)  (cx, cy) or (x, y)  c(x, y)

10. If given a preimage and an image how do you find the scale factor? A’ or A need to be either the x’s or the y’s of one coordinate, Unless the values are zero.