IM 7.1.5 Lesson: The Size of the Scale Factor
Solve the equation mentally.
Here is a set of cards. On each card, Figure A is the original and Figure B is a scaled copy.
Sort the cards based on their scale factors. Be prepared to explain your reasoning.
Examine cards 10 and 13 more closely. What do you notice about the shapes and sizes of the figures? What do you notice about the scale factors?
Examine cards 8 and 12 more closely. What do you notice about the figures? What do you notice about the scale factors?
Triangle B is a scaled copy of Triangle A with scale factor . How many times bigger are the side lengths of Triangle B when compared with Triangle A?
Imagine you scale Triangle B by a scale factor of to get Triangle C. How many times bigger will the side lengths of Triangle C be when compared with Triangle A?
Triangle B has been scaled once. Triangle C has been scaled twice. Imagine you scale triangle A times to get Triangle N, always using a scale factor of . How many times bigger will the side lengths of Triangle N be when compared with Triangle A?
Your teacher will give you 2 pieces of a 6-piece puzzle. If you drew scaled copies of your puzzle pieces using a scale factor of , would they be larger or smaller than the original pieces? How do you know?
When everyone in your group is finished, put all 6 of the original puzzle pieces together like this:
Next, put all 6 of your scaled copies together. Compare your scaled puzzle with the original puzzle. Which parts seem to be scaled correctly and which seem off? What might have caused those parts to be off?
*Revise any of the scaled copies that may have been drawn incorrectly.
If you were to lose one of the pieces of the original puzzle, but still had the scaled copy, how could you recreate the lost piece? Explain.
What is the scale factor from the original triangle in the applet below to its copy? Explain or show your reasoning.
The scale factor from the original trapezoid to its copy is 2. Draw the scaled copy.
The scale factor from the original figure to its copy is ³⁄₂. Draw the original figure.
What is the scale factor from the original figure to the copy in the applet below? Explain how you know.