you can't
You cannot make four triangles our of a quadrilateral by ONE line through it. One line can give you at most two triangles. Two lines, each running from one vertex of the quadrilateral to the opposite vertex, will give 4 triangles.
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).
No.
Rhombus
you can't
A parallelogram.
You cannot make four triangles our of a quadrilateral by ONE line through it. One line can give you at most two triangles. Two lines, each running from one vertex of the quadrilateral to the opposite vertex, will give 4 triangles.
Four equilateral triangles make up another equilateral triangle.
No two equilateral triangles do not make a square but two right triangles do.
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).
No.
Rhombus
a larger equilateral triangle
No but they will make a hexagon
Yes
It has a four sided square base and four other triangular sides reaching up to an apex. It is a pentahedron. If the four triangles are equilateral, it is known as a Johnson solid, and six of the pyramids will fit together to make an exact cube. If the four triangles are not equilateral, then they are isosceles.