Can someone help me with this geometry problem?

First of all this has nothing to do with school or grades. I am making a building and am confused about how to find a certain angle.
Click here for the diagram. (You may need to brighten your computer screen.)
I am looking for θ, and can’t seem to find it. θ is the angle from the dotted line (unknown length) to the line that is SQRT(9090)ft, and from the dotted line to the line on the bottom. Do I need to give you more information? Thanks for the help!
In case it is hard to read, here are the numbers on the diagram:
21’
93’
SQRT(9090)’
arctan(21’/93’)
67’6’’