All have 4 sides. That’s what I would put. Good luck and don’t copy links they’re most likely viruses
Answer:
6.7
Step-by-step explanation:
Here, we can apply cosine law, 
We the plug in values: 
and solve that CB is around 6.7
I think that it is attempt. If i am wrong, sorry.
Answer:
400
Step-by-step explanation: