How many unique triangles can you make with one angle 90 and the other angle is half that measure

One. If one of the angles is 90° then there are only 90° degrees left for the other two angles. If angle two is half of 90°, that would make it a 45° angle meaning there is only another 45° left. Every triangle can have a total of 180° when you add all their angles together.

Only rhe obtuse triangle