@10P8TRIOT@RHSTUDYZONE I'm talking about Y.
Just because the top-right angle is 90°doesn't guarantee that the angles are 48° and 42°.
On the other hand, if the bottom-right angle is also 90° and the two lines are parallel, then you won't need to calculate the value of XY to find the sum of X and Y.
@10P8TRIOT@RHSTUDYZONE Unless the bottom angle is also a right angle, we can't prove that the angles are 48° and 42°.
Isn't the necessary information that they're parallel?