Answer:
x = 90
Explanation:
A line will ALWAYS equal 180 degrees, so we know that one angle is <90 and we have to find x, which is the other angle of the line.
So, x + 90 = 180
You can either solve the equation for x or you can just subtract 90 from x, which is the easier way.
180 - 90 = 90
So, x = 90
I hope this helps, and explains it!