Answer:
angle xyb will measure 123 degrees.
Explanation:
because we know that angle ayz is 57 degrees and angle xyz is 90, we find that angle xya measures 33 degrees by subtracting 57 from 90. then, we can find angle xyb by subtracting 33 from 180, getting 147 degrees. when we add 147, 33, and 57, we get 237 degrees. finally, we subtract 237 from 360 and get 123 degrees, our final angle. hope this helps:)