Answer:
b = 30 degrees
Step-by-step explanation:
For this problem, the red square within the drawing denotes that the angle is 90 degrees. We have an angle bisector of 60 degrees + b degrees which must add up to 90 degrees. So you can work the following:
90 = 60 + b
90 - 60 = 60 - 60 + b
30 = b
Hence, b is 30 degrees.
Cheers.