Answer:
45
Step-by-step explanation:
You want to know how many more degrees 135 degrees is than 90 degrees.
Difference
The difference of two numbers is found by subtraction. This tells you how much more you need to add to the smaller one to make it equal to the larger one:
135 -90 = 45
You need to count 45 more degrees to get from 90 to 135 degrees.