This type of "triangle" would be the result of calculus-type calculation where one side of the triangle approaches zero in length. The figure will only be a true triangle (by definition, 3 sides, 3 angles) so long as the side is still approaching zero, no matter how small. Once the side becomes zero, the figure will fit the description in the question above, but will no longer be considered a triangle, for practical purposes.
vertex
the vertex is the common endpoint
Vertex
Every side of a polygon shares endpoints, one each with the two sides next to it.
The sides of a triangle do not meet in a point, so there is no "the common point".
Opposite sides.
In math, adjacent refers to two angles or sides that share a common vertex and side but do not overlap. Adjacent angles add up to 180 degrees in a straight line, while adjacent sides share a common endpoint or vertex.
Vertex!! =)
vertex
the vertex is the common endpoint
An angle consists of two rays called sides with a common endpoint called the vertex.
point of intersection of the sides of the angle; the vertex
Vertex
Parallel sides, non-adjacent sides, skew sides in 3-d shapes.
Every side of a polygon shares endpoints, one each with the two sides next to it.
An angle consists of two rays called sides with a common endpoint called the vertex.
The sides of a triangle do not meet in a point, so there is no "the common point".