Tetrahedron
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"
No.
A solid with four faces for maths is a tetrahedron.
A pyramid. The square being the base and the triangles the 'sides' - each having a side connected to a side of the square - the other sides connected to 'neighbor-triangles'.
Isosceles TetrahedronA solid with four faces is a tetrahedron. Each of the faces is a triangle. If all the triangles are congruent, you have an isosceles tetrahedron.
tetrahedron
Tetrahedron
The answer is a pyramid.
A tetrahedron is a solid figure with four flat surfaces that are triangles. Each face of a tetrahedron is a triangle, making a total of four triangular faces in the shape.
The tetrahedron, consisting of four regular triangles.
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"
A triangular-based pyramid - it consists of four equilateral triangles, joined at the points.
Square Pyramid
Pyramid with a square base. One square side on the bottom and four triangles meeting at a point on the top.
No.
A solid with four faces for maths is a tetrahedron.