Yes.
a four faced triangle is called a tetrahedron
Pyramid
A triangle.
None. A square triangle is an oxymoron - it cannot exist!
A triangle.
That is the definition of a triangle. If it did not have three sides it would not be a triangle. If it did not have three angles, it would not be a triangle.
A triangle with three sides is a polygon.
An equilateral triangle is a triangle in which all three sides are equal. An example is a triangle with 60o in all three corners.
A triangle with three congruent angles
a triangle is a polygon with three sides.
Three is to triangle as eight is to octagon.
triangle