This is Not a Rectangle

Published by patrick honner on

After having fun exploring rigid and non-rigid frames, I hung one of our indeterminate quadrilaterals up on the board.  The next day, we were proving a theorem about orthodiagonal quadrilaterals, and the final step concluded that a particular quadrilateral was actually a rectangle.

I found a cute little spot to finish our proof.

This elicited a few laughs from students who appreciated the irony.

But apparently, some students in a later class did not appreciate it.  They felt the need to chime in.

As a general rule I must oppose mathematical graffiti, but it’s hard not to respect their position.

patrick honner

Math teacher in Brooklyn, New York


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