Target 2-A, Target 2-B, Target 2-C, Target 2-D, Target 2-E, Target 2-F

Target 2-G

  

Explain how properties of figures are affected by size transformations.

 

Sample Question

Suppose a shape B′ is the image of a shape B under a size transformation of magnitude 3.

  1. Make a list of properties of B that are also properties of B′.
  2. How are corresponding distances in B and B′ related?
  3. If B has area 63 cm2, then what is the area of B′?

Sample Response
  1. B and B′ have the same shape. So if B has perpendicular or parallel sides, then the corresponding sides of B′ are also perpendicular or parallel.
    The corresponding angles measures of the two figures are the same.
  2. If you consider a distance in B, the corresponding distance in B′ will be 3 times the size. So if a distance in B is 5 meters, then the corresponding distance in B′ will be 5·3 = 15 meters.
  3. If B has area of 63 cm2, then the area of B′ will be 63·32 = 567 cm2.

Here's a picture that helps me see why the area gets 9 times bigger: