

Over-constrained sketch; could someone help me spot the error here, please?
Hi,
I'm posting some photos: the first one shows the instructor's project, and the second one is mine. Could someone help me out and tell me what I drew incorrectly? We learn from our mistakes, so I need to know what I did wrong.
In the first photo, he is adding a sketch dimension, but I can't do it; I get an "over-defined sketch" error message. I was wondering if anyone could spot the error in the second photo?
If you need more photos, let me know
thank you everyone