The answer key says that
∠ACD = ∠EDB
∠CAB = ∠DEB
and therefore the slopes are equal.
But I don’t understand why can’t ∠ACD = ∠DEB, which would then make ∠CAB = ∠EDB.
Is it because we’re using the order of the letters to follow along in the graph? If so, then I can see it. But then do we always follow the order of the letters? Why?
Thanks in advance for anyone’s help!