A 3D shape could be:
A square!
A shape with a square base and four triangular sides is a pyramid.
A pyramid has 1 square base.
a a square based pentagon
A square based pyramid.
The shape in question is called a square pyramid.
A square!
A shape with a square base and four triangular sides is a pyramid.
A pyramid has 1 square base.
The base
A square based pyramid.
a a square based pentagon
A square pyramid is a pyramid whose base is in the shape of a square.
Square
A square.
square
circle triangle square