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
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.
One square and four triangles.
4 right triangles
2 are in a square
A square based pyramid has 4 triangular faces and 1 square face.
two
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)}
27, but you will have to prove it.
the answer is pyramid