# The area of a triangle!

I walked into my long block geometry class today. And as I was opening the door a kid super excitedly said I GOT THE TRIANGLE PROBLEM!!! He became obsessed with this thing they were asked to do, and it was the sheer joy in his voice when he expressed it — that moment of conquering and elation and wanting to shout it to the world — that I wish I could have captured.

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I had developed this “activity” for the long block geometry class, and I was pretty down on it. I still don’t know if the time we’ll spend on it is worth the take-away for the activity. But the setup involved kids sitting in front of a wall, at two different distances from the wall, and figuring out where the first person should roll the ball to the wall so it hits the wall and bounces to the other person.

Then, naturally, the question developed to having the ball hit two different walls (walls that meet at a corner) to get to the other person. I actually didn’t plan that, but then I had all groups play with that to get some intuition.

Then a student said something about this being like “pool” and other kids were like “oooooh, we’re learning pool!”

I don’t know — as I said — if the payoff for this activity is going to be worth it, as designed. But the part I was worried about — the “let’s go in the stairwells and roll some pingpong balls” wasn’t seen as “stupid” and “boring” by my kids (which was the thing I was afraid of).

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At the start of precalculus, a student came up with a guess for the general equation for a particular term in an arithmetic sequence. He was slightly wrong, but it was awesome, because he came up with it organically from what we were doing. And many of the kids latched on and understood what he said — which made the rest of the class so much smoother!