Answer:
20 degrees
Step-by-step explanation:
A triangle's angles should 180 degrees added together, so 90 + 70 = 160, leaving 20 for the last angle.
The rays shown in the pictur: Ray VX, YZ , XY, ZV..... Plus more!
The graph looks like this, on the enclosed pic:
One feature is that it's periodic and torn (has cut-off points), meaning the domain is the same as in case of tan(x): x€R and x =/= π/2+πn.
The range equals the range of arcsin(x): -π/2<=y<=π/2 OR y€[-π/2;π/2]
Hope could understand and if it helped! :)