This is overdetermined. Without looking at the ratio (except for the order of the sides) the actute angles in a right triangle are complementary so the answer must be:
Answer: A=35°, C=90°, B=55°
We can do it the way they like.
7+18+11 =36
so to get 180 degrees we need to scale the ratio elements by a factor of 5.
7:18:11=35:90:55
A is the smallest. We see C is indeed a right angle and B is complementary to A.