To start our unit on similarity in geometry we started with a review of isometries from first semester and then moved on to using “rubber band stretchers” to create dilated images of given figures.
Idea modified from here
After they completed their figures they were instructed to measure different sides and angles and try to determine a pattern for each.
Many were quick to see that the angles remained the same, but it took a little coaching for them to piece together the pattern occurring with the sides. I think this was primarily so because students kept tending to measure only one pair of sides and not explore the others.
Now if I could just figure out how to decrease the number of wayward, projectile bands from groups who finish quickly.