General triangle rule (30:60:90)

Hi, if a right triangle has one angle equal to 30 (or 60) you KNOW the other angle has to be 60 (or 30) and thus the longest side is 2 times the shortest side.

Does this equivalency work both ways? (I can't get a clear sense of it from various answer guides and just want to make sure)

If you know a right triangle has the longest side equal to two times the shortest side, do you then KNOW it HAS to be a 30:60:90 triangle?

Thanks