Answer:
y = 42
Step-by-step explanation:
if we need to find the value of y we need to
y + 90 + 48 = 180 (angle sum property of triangle and we used 90 here because the line which is crossing and y and z's line is 90 hence the other side of the line will also be 90)
y + 138 = 180
y = 180 - 138
y = 42
We can even cross-check by placing the value of 42 instead of y
42 + 90 + 48
42 + 138
= 180
Hence proved y = 42
