If you mean a "triangle" it is a 3 sided shape with interior angles adding to 180 degrees and exterior adding to 360 degrees.
Trinagle
It depends on what information you do have.
Scalene Trinagle
Area of a triangle = 0.5*base*perpendicular height
there is a right triangle an iscosoles trinagle and another one i cannot remember=P
i trinagle that is the coler gold
trinagle,trinagle,circle
If an isosceles triangle is one that has two equal sides,then I guess every equilateral trinagle is isosceles.
3
Trinagle
One
Scalene Trinagle
It depends on what information you do have.
Obtuse
no it's a polygon not a polyhedron
no because it wouln'y be a trinagle
base times height divide by 2