Answer: The answer would be 315 if you are looking for the remaining angle if you're looking for the actual measure of the remaining section of the circumference, then the answer would be approximately 49.481
Explanation:
Because the remainder of the circle is the answer you're looking for, you can subtract 45 from 360 and get your answer, whenever you know the measure of one angle, and you are looking for the remaining angle, you can use this strategy.
You already know the angel of the remainder, and you can use this to find the section of the circumference shown. First you need to find the circumfrence, to do this you must use the equation C equals pi radius squared. You put 9 in for the radius and you get approximately 56.55, you then divide this by 360 and get 0.15708333, you then multiply it by the angle you found early, 315. You then should get approximately 49.48125.