1/19/07
The Stretching and Shrinking lessons are coming to an end, and I am sitting here trying to figure out whether my students have learned what I wanted them to learn. Yesterday, my teammate Yvette and I gave a quiz as a checkup on investigations 1, 2, 3, and 4. The grades from this quiz are all over the board. I have three A's, four B's, three C's, one D, and one F. Yvette has similar results. The question now is: Did the students learn all of the essential concepts? I know that the ones who received A's and B's do understand the essential concepts. However, I don't think that the students in the C range understand the essential concepts.
Our quiz covered these skills:
- Characteristics of similar figures
- Using scale factor to find the perimeter and area of a
new figure - Using ratios to evaluate whether figures are similar
- Equivalent ratios
- Finding scale factor from a larger to a smaller figure,
and vice versa - Finding missing side lengths
- Using rules to create similar figures on coordinate grids
The students who struggled the most on this quiz had the most trouble with these two questions:
- How do you use scale factor to determine whether a figure
stretches or shrinks?
- Stretches: _______________________________
- Shrinks: _________________________________
- Which of the following rectangles is similar to a 10 by 15 rectangle?

Obviously, these were not the only questions that these students did not understand/answer correctly.



