Answer:
b = 55 degrees
Explanation:
The angles 30, a, b and 45 must sum up to 180 degrees
Subtracting (30 + 45) from both sides leaves us with a + b = 105 degrees.
But b = a + 5. Substituting a + 5 in the equation above yields
a + a + 5 = 105 degrees, so that
2a = 100 degrees, and a = 50 degrees. Then b = a + 5, or b = 55 degrees.