A right triangle. (This is a joke.) A right triangle is one that has a 90o angle.
It depends on what kind of triangle.
right triangle
No not never
The kind of triangle with two sides the same length is an isosceles triangle.
An obtuse triangle.
a right triangle
Yes, a triangle is always concave. * * * * * How wrong can you get! A triangle is always convex and NEVER concave.
The not wrong part of a triangle
It depends on what kind of triangle.
If you mean "triangle", a triangle can never have two parallel sides.If you mean "triangle", a triangle can never have two parallel sides.If you mean "triangle", a triangle can never have two parallel sides.If you mean "triangle", a triangle can never have two parallel sides.
Never but an isosceles triangle can sometimes be a right angle triangle
Never
right triangle
"Congruent" means "same shape and size as the other one". So one thing all by itself is never congruent. It needs something else to be congruent with. An isosceles triangle is never congruent to a scalene triangle, sometimes congruent to any other kind of triangle, and always congruent to another isosceles triangle that's congruent to the first one.
No not never
No, you would need at least 4 points to create a concave polygon.
A triangle can never include a right angle and an obtuse angle together in it.