Answer:
Bear with me here
Explanation:
I don't actually know how to solve this, I have geometry later this year. I just hope to be able to set it up for you.
Ok, so BE and CE are perpendicular. This means that they make a 90 degree angle. we can write in the boxes to signify if you want. We also know that the angles CDE and DCE have the same angle. I don't know how to put this is math terms, but that means that ADE and BCE have to be the same as well. If x(the angle of ADE and BCE)is the same, then CDA must be x + (mystery angle). if ADE and BCE are the same, and a triangle's angles add up to 180, then DAE and EBC must be the same as well. Not sure if this actually helps, I'm not able to give a straight answer but it's the best I can do with what I know.