# B Question D2 group

1. Jan 31, 2017

### LagrangeEuler

2. Jan 31, 2017

### Staff: Mentor

What happens if you reflect a rectangle with two different side lengths at one of its diagonal?

3. Jan 31, 2017

### LagrangeEuler

They change sides I suppose. So when I did that transformation longer side if it was horizontal it will be vertical after that transformation. Right?

4. Jan 31, 2017

### Staff: Mentor

Yes. If it was first lying down, the it's standing up afterwards, so it changed. This doesn't happen if you reflect it along the half sections parallel to the borders. By the way, rotation also makes a difference, even if rotated by $180°$. Do you know why?

5. Jan 31, 2017

### LagrangeEuler

6. Jan 31, 2017

### dkotschessaa

7. Jan 31, 2017

### dkotschessaa

Have you tried these physically with a piece of paper?

8. Jan 31, 2017

### Staff: Mentor

Yes, that's true. But what happens if you add an orientation, a tiny arrow which shows a direction you could walk along the rectangle? Then you see, that rotation and reflection are different, although the non-oriented figure is the same. (Not important to your original question though, but useful to remember.)

9. Jan 31, 2017

### LagrangeEuler

Thanks a lot Sir for your help.

Last edited: Jan 31, 2017