A regular tetrahedron
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.
No, a square is not made up of four equilateral triangles. A square has four equal sides and four right angles, while equilateral triangles have three equal sides and three equal angles, each measuring 60 degrees. However, you can arrange two equilateral triangles to form a rhombus, which can be manipulated to fit within a square, but they do not constitute the same geometric shape.
Put the triangles in a line alternately pointing up and down.
there are more than four: equilateral, right, obtuse, acute, scalene
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 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.
tetrahedron
A parallelogram.
No, two equilateral triangles do not make a square. A square has four equal sides and four right angles, while an equilateral triangle has three equal sides but three angles that add up to 180 degrees. When two equilateral triangles are put together, they do not form a shape with four equal sides and four right angles, which is the defining characteristic of a square.
Put the triangles in a line alternately pointing up and down.
Four equilateral triangles make up another equilateral triangle.