No.
No, because angels don't come to earth for triangles. However, you can certainly have right angled equilateral triangles.
No. Only right triangles do, and not all triangles can be right triangles. Equilateral triangles, for example, are always 60°-60°-60°. Isosceles and scalene triangles can be right triangles; all isosceles triangles have the additional useful property of being able to be split into two right triangles.
Yes
No because only right angle triangles have 2 acute angles
no
Circles, some triangles, and irregular polygons
All triangles have three angles.
All right-angles triangles. That is triangles that contain one angle at 90 degrees.
Yes- but not all isosceles triangles are right triangles. Isosceles means that two sides are the same length, and two angles are the same.
No, scalene triangles can be obtuse, right or acute triangles. A 3 - 4 -5 right triangle (lengths of the sides) is one example of a right-scalene triangle. In fact, with the exception of the [45°, 45°, 90°] right triangle (which is isosceles) all other right triangles are scalene.
The sum of the angles in any triangle is always 180 degrees. This holds true for all types of triangles, whether they are acute, obtuse, or right triangles. Each angle can vary, but their total will always equal 180 degrees.
no only right triangles