I dont quite remember the formula, but I belive that 30 would be correct because if im remembering correctly the formulas are "a + b = c" and "c - (a/b) = (a/b)
This is a isosceles triangle and also a right triangle, so it means it have an 90° ingernal angle and the other two internal angles have the same value. Remember that the sum of the internal angles of a triangle is always 180°, so:
