The Great Pyramids at Giza are, but the Meso-Americans were truncated.
Rohmbus is a four sided figure (quadrilateral) that is made up of two equilateral triangles
It would depend on the triangles, but assuming they were equilateral or isosceles, a trapezoid if alternated in a line.
Infinitely many. When you have one equilateral triangle, you can join up the midpoints of its sides to make into 4 more equilateral triangles. And then each one of those can be split up and so on.
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.
square
The Great Pyramids at Giza are, but the Meso-Americans were truncated.
Rohmbus is a four sided figure (quadrilateral) that is made up of two equilateral triangles
It would depend on the triangles, but assuming they were equilateral or isosceles, a trapezoid if alternated in a line.
square
Infinitely many. When you have one equilateral triangle, you can join up the midpoints of its sides to make into 4 more equilateral triangles. And then each one of those can be split up and so on.
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.
Many different types, but mostly equilateral triangles.
3
In effect an equilateral triangle is made up of two right angle triangles joined together so use Pythagoras' theorem to find the height:- 182-92 = 243 and the square root of this will be the height of the equilateral triangle which is about 15.588 cm
Put the triangles in a line alternately pointing up and down.
Four equilateral triangles make up another equilateral triangle.