Other contributors have said "How is the right triangle still important?" is the same question as "How is the right angle triangle still important?" If you believe that these are not asking the same thing and should be answered differently, click here
The angle directly opposite the hypotenuse is always 90o in a right angle triangle and if you know the other sides you can work out the other angles using one of the three trigonometry equations....
No, if there was more than one right angle, it would be physically impossible for the shape to be a triangle. It would have to be a square or rectangle.
Remember, all the angles in a triangle add...