It depends entirely on the size of the triangles and the size of the square.
no triangles
It depends on the size of the square and the sizes and shapes of the triangles.
You can put 2 triangles in a square or you can call it a quadrilateral.
27, but you will have to prove it.
A square based pyramid has 4 triangular faces.
a square pyramid has 4 triangles
no triangles
One square and four triangles.
It depends on the size of the square and the sizes and shapes of the triangles.
You can put 2 triangles in a square or you can call it a quadrilateral.
4 right triangles
2 are in a square
A square based pyramid has 4 triangular faces and 1 square face.
For a square with side S. There will be the 4 small triangles each with sides {S/sqrt(2),S/sqrt(2),S}. Then also you can 'see' 4 larger triangles, each with sides {S,S,S*sqrt(2)}
two
27, but you will have to prove it.
the answer is pyramid