Hello
This is a right angle as you can see by the small square at the bottom. So this means that it is 90 degrees.
Because we already know part of the 90 degrees, we can do 90-50 degree which leave us with 40 degrees.
So as we look at 8x, it needs to equal 40
- 8x=40 divide both sides by 8
- x=5
Hope this helps!