A pyramid.
There is a contradiction in your question. If the base has four equal sides then is it a square so not all the faces are Triangles. However if the base is a square and the rest of the faces are triangles then your object is a "Square-based Pyramid"
triangular pyramid
No. Usually the base is not.
a pyramid
They are triangles.
4 faces are triangles and 1 face is a square the square face is the base of the pyramid
The base will be a square, all the rest of the faces are triangles.
a pentagonal pyramid it has five triangular sides that all meet at a point at the top. the base is a pentagon
No because it has a square base and 4 triangular faces
A three-dimensional figure with a polygon base and triangular faces that meet at a common vertex is called a pyramid. The base can be any polygon, such as a triangle, square, or pentagon, and the apex is the common vertex where all the triangular faces converge. Pyramids are named based on the shape of their base, such as triangular pyramids or square pyramids.
A pyramid.
A regular octahedron is a Platonic solid with equilateral triangles for each of the faces. A heptagonal pyramid is an octahedron with one heptagon (a seven sided figure) as its base and 7 triangles, one attached to each side, meeting at the either vertex.