Step 1: Try to draw a triangle showing two obtuse angles.

            NOTE: Not possible

Step 2; Theoretical proof.


         Let the angles of the triangle be a, b and c. Let a be the obtuse  angle.

        The sum of all the angles in any triangle is 180°. a + b + c = 180°.

        If a > 90° then b + c must be less than 90°. Therefore, b and c must be

        acute angles.