I presume the question is meant to be: How many sides does a pyramid have? The answer is 4 or more. A pyramid has a polygonal base where the polygon can have 3 or more sides. Corresponding to each of these sides there will be a triangle rising to the apex of the pyramid. In all, a pyramid whose base is a polygon with n sides will have n+1 faces (sides).
A pyramid is a generic term used to describe a polyhedron with a polygonal base and a number of triangles rising from that base to meet at an apex. A pyramid whose base is a polygon with n-sides (or vertices) has n+1 faces, n+1 vertices and 2n edges, where n >= 3. So a pryramid can have 4 or more faces.
The answer depends upon what is meant by "have 3 triangles?" The definition of a pyramid is "a solid having a polygonal base, and triangular sides that meet in a point." (Random House Webster's Unabridged Dictionary) Typical pyramids have a 4-sided quadrilateral base and 4 triangular sides, which means that it can be loosely said to also "have" 3 triangles as well as "have" 4 triangles. A pyramid with a triangular base would also have…
A pyramid can have an infinite number of sides other than two. If it has one (or an infinite number of) side(s), it is considered a cone. If it is, for example, a hexagonal pyramid, it will have six sides. A triangle-based pyramid has three sides. A square-based pyramid, commonly the structure used by ancient Egyptians, has four sides. There can be pentagonal pyramids, hexagonal pyramids and so on.
Pyramids are classified by the shape of their base. A triangular pyramid has a triangular base and three triangular side faces. A square pyramid has a square base and four triangular sides. A pentagonal pyramid has a pentagonal base and five triangular sides. A hexagonal pyramid has a hexagonal base and six triangular sides, and so on.