No
The sum of the angles in any triangle is 180. This includes Equalateral triangles.
A right triangle can have 2 equal angles if they are each 45° (any other right triangle will have no equal angles)
No right triangle can have any obtuse angles inside it.
A right angled triangle can have two 45° angles if it is isoceles
No
The most right angles a triangle can possibly have is 1. Any more than that, and it has to be a quadrilateral.
Any triangle that is not a right angle triangle
The interior angles of a triangle add to 180 degrees. This is true for any triangle, whether it is obtuse angled, right angles or acute.
It depends what type of triangle it is. If it is a scalene triangle, ie. a triangle with three different length sides and angles, then it won't have any lines of symmetry. If it's an iscosoles triangle, ie. a triangle with two sides and angles of equal length, it has one line of symmetry, but if it's an equalateral triangle, ie. a triangle with all sides and angles the same, then it has three lines of symmetry.
No triangle has any 90-degree angles unless it's a right triangle. Most triangles are not.
The sum of the interior angles of ANY triangle is 180 degrees.
0. A right triangle, by definition, will never include any obtuse angles.