Let angle CBD=x
Now let angle ABE=3x
Thus angle ABE = 3 times angle CBD
No seriously, take it from someone whos completed the mathematics course (prelim and hsc) in 14 months and is now working through 4 unit, you need at least one value, other wise any angle in your diagram can equal anything less than 180 degrees.
the only thing you might want to try is getting out your protractor and measuring the angles in the book- might come out like that