## Thursday, August 16, 2012

### Parallel Lines & Transversals

I've been so caught up in my classroom that I've taken a break from posting ISN stuff.  I went through my various ISN's and picked some pages that I haven't shared yet.  Today I'm going to show off one of the last ones I did with my summer geometry class.

This is on the angles formed by parallel lines & transversals.

First I handed out this picture which many of them had seen before and we discussed which angles were congruent.  I told them they couldn't color yet though.

They chose a crayon and colored angle 1.  Then I let them also color angle 4 because we had discussed vertical angles the day before.  Next I introduced corresponding angles and let them color 5 and 8.

On this sheet (which is under the diagram) they recorded the descriptions and listed examples.  I would give them one example and they found the rest.

Then we did the same with alternate interior/exterior angles, showing and labeling on the figure where the interior and exterior are.

After going through this, I had them do an activity I found on Dan's post here.  I loved it because it was really challenging for them.  For the kids that I had, this was their first real introduction into proofs or having to really justify their work.

If I were to do this again, I would go through the first few steps with them more slowly.

I would also make plenty of extra copies.  A lot of kids didn't really listen to directions and just filled in every angle with either 130 or 50 and said they were done.  They then needed an extra copy to start over.

Once they got the hang of it though, they did really great.  I loved that there were many different ways to justify a lot of the angles so most of the kids had different work showing me that they really thought about it them self.

The really nice thing about this activity was that the kids all referred back to their colored diagram the entire time.  They would look at the puzzle and then try to find two angles that looked similar and then they would look up the name of the angle pair.  As math teachers we might overlook the significance of the colors in this activity because we can easily "see" that the angles are equal, but we need to remember that not all kids see it the same way.  The color really helps this idea to clearly stand out.