Answer:
75 degrees
Explanation:
Well, I mean, that this is simple (I think) because a complementary angle is angles that add up to a 90 degree angle.
So if an angle is three times than another and add up to 90 degrees,
then it has to be 75 and 25 because 75+25=90 and 75/3=25 and 25x3=75.
Hope this is what you're looking for!