Yes, the definition of a polygon is any closed figure with straight sides.
yes
A right angle triangle
A 3 side polygon is a TRIANGLE.
triangle
a right triangle
When the triangle is right, the orthocenter is the polygon vertex of the right angle. Intuitively this makes sense because the orthocenter is where the altitudes intersect. Hence, in a right triangle, the vertex of the right angle is where you would expect the altitudes to meet, at 90 degrees, where the legs of the right triangle are perpendicular.
A triangle
Any polygon can have a right angle. A right angled triangle is an example.
it can be a triangle that is right, acute, or obtuse
No.
right triangle
A right angle triangle
An isosceles right angled triangle.
No, but an equilateral triangle is a regular polygon with 3 equal sides and 3 equal angles.
A polygon can be any one of them.
A triangle.
equilateral triangle
Any polygon can have at least one right angled - for example a right angled triangle. An example of an irregular polygon with only right angles is a rectangle.