How to find angle beta in drawing, given BAC is right, AB = AC, BC = CD

[wellmath]

I can not find the beta angle in this problem. Can someone help?
it looks like the answer should be beta = 30 but I can not prove it.

 

[Dr.Peterson]

I can not find the beta angle in this problem. Can someone help?
it looks like the answer should be beta = 30 but I can not prove it.


View attachment 9240

Try this: drop a perpendicular from D to s at E, and think about triangle CDE. I found it helpful to assign a length to a segment; I took AB = 1.