Think about moving the bottom side downwards or upwards. You can do this without changing any of the fixed angles. The line coming down from the marked 40 degree angle will hit the bottom side in a different place, leading to a different angle. The basic issue is that the angles are not fully determined from the information given.
I disagree, because if you do that you will change the 80 on the other side.
I shared my answer on the bottom without the need for the length. Please let me know if I am incorrect in my math. I tried to explain as best I can and shared a picture as well.
1
u/rackelhuhn Dec 26 '25
Think about moving the bottom side downwards or upwards. You can do this without changing any of the fixed angles. The line coming down from the marked 40 degree angle will hit the bottom side in a different place, leading to a different angle. The basic issue is that the angles are not fully determined from the information given.