1. The user's question "so what is the triangle" is unclear since it lacks context. 2. A triangle in mathematics is a polygon with three edges and three vertices. 3. It can be characterized by its side lengths and angles, e.g., equilateral (all sides equal), isosceles (two sides equal), or scalene (all sides different). 4. If you have a specific triangle problem or question, please provide details such as side lengths, angles, or what needs to be found.