Answer:
The answer in the procedure
Step-by-step explanation:
Part A)
we know that
The measures of interior angle in a triangle must be equal to 180 degrees
In the triangle AUL


-----> by supplementary angles


The sum of the two nonadjacent interior angles is equal to

therefore
m<4 is equal to the two nonadjacent interior angles
Part B)
----> see the Part A)