Rohmbus is a four sided figure (quadrilateral) that is made up of two equilateral triangles
A four faced figure is a tetrahedron. If they are all congruent triangles, they are all equilateral triangles and it is a regular tetrahedron - one of the 5 Platonic Solids.
Put the triangles in a line alternately pointing up and down.
there are more than four: equilateral, right, obtuse, acute, scalene
Sort of depends on how the two triangles are beforehand. One nice way to make four equilateral triangles from six matchsticks is to make a tetrahedron (a triangular pyramid).
Rohmbus is a four sided figure (quadrilateral) that is made up of two equilateral triangles
A tetrahedron is a three-dimensional figure with four equilateral triangles. Every pyramid with a triangle as the base is a tetrahedron.
A triangular-based pyramid - it consists of four equilateral triangles, joined at the points.
A four faced figure is a tetrahedron. If they are all congruent triangles, they are all equilateral triangles and it is a regular tetrahedron - one of the 5 Platonic Solids.
A three-dimensional figure or shape, such as a tetrahedron, has four faces. These faces are equilateral triangles. A tetrahedron also has four vertices and 6 edges.
Quadrahedral is not a word. A tetrahedron (tetra- is the Greek prefix for four, as opposed to quadra-, which is Latin for four) is a four-sided solid figure, basically a pyramid formed from four equilateral triangles.
A tetrahedron has four equilateral triangles as sides
A four sided figure would be a tetrahedron and a 20 sided would be an icosahedron. They both have equilateral triangles for faces so your question is a little incomplete.
A parallelogram.
tetrahedron
Put the triangles in a line alternately pointing up and down.
Four equilateral triangles make up another equilateral triangle.