## Monday, October 15, 2012

### Congruent vs. Similar Shapes While Appealing To Fashion Senses

The goal of this activity is to help make the distinction between the two concepts of similar shapes and congruent shapes. We will do this by appealing to our students fashion senses.

The Hook:

Do you guys think other people in this school copy your style? Give me an example without using any names?

Transition:

What about shoes? Has anyone ever went out and purchased the same pair of shoes you bought or wanted? Now lets be honest, did they purchase a similar pair or an exact pair? Were they the same style, color, etc? What about the same size? So would you say this person purchased the exact pair of shoes you wanted or a similar pair?

In math we use terms like this when dealing with stuff like shapes. Except we don't say similar or exact, we say similar or congruent.
For example,
These are similar triangles

These are congruent triangels

Whats the difference?
So let's return to our example of shoes. If we (informally) accept that similar shoes are the same shoe but in different sizes than what would congruent shoes look like? Same shoe, same size!

Classroom Exercise:

Everyone take out a piece of paper and draw a line down the middle. Label one column Similar and the other column Congruent. I want each of you to go around the room and see who has similar or congruent shoes, jackets, shirts, pants, jewelry, etc. Anything but socks or underwear! We'll keep it PG for this exercise!