Impossible Triangles TN
Teacher Notes
These are just a few notes about this activity as well as the solutions (see table below)! This is activity is so simple in nature that there is not a great need for lots of discussion here. I just wanted to say again how I feel this activity works best when students are given no introduction or clues about how to go about this. My reason for this is the desire to see students reach for the tools they have at their disposal by themselves. By simply asking students if the triangles can exist or not, the task is easily understood. From my experience, the discussion then ensues and gets more and more detailed as they go on. The activity has been a success if students start using the language of trigonometry themselves as reasoning without being prompted to do so!
The table below shows the solutions for this exercise. The left hand column shows the letter of the triangle and the right hand column shows either 'T' for True or 'F' for False.
| A | T |
| B | F |
| C | F |
| D | T |
| E | T |
| F | T |
| G | T |
| H | T |
| I | T |
| J | F |
| K | F |
| L | F |
| M | F |
| N | F |
| O | T |
| P | T |
| Q | F |
| R | F |
| S | T |
| T | T |
| U | F |
| V | F |
| W | F |
| X | F |
| Y | T |
| Z | F |