Question

The three inside angles (A,B and C) of a right angled triangle are in the ratio 7:18:11

Answer 1

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.