A triangle is defined as a closed shape with three straight sides and three angles, not by its orientation.
A square-based pyramid
A pentagon for a base, five triangles reaching up to a point on top.
It can, but it doesn't have to. The base can be any polygon, as long as the sides are triangles that come to a point at the top.
A pyramid - it has a square base, and four triangles meeting to a point at the top.
No, the pyramids of Egypt are not equilateral triangles. They are three-dimensional structures with a square base and four triangular faces that converge at a point at the top. The triangular faces are typically isosceles triangles rather than equilateral triangles. The angles and proportions of the pyramids vary, but their design is not based on equilateral triangles.
Pyramid with a square base. One square side on the bottom and four triangles meeting at a point on the top.
Postulates is, I believe, the starting point of reasoning that two triangles are the same.
To draw a trapezium with three triangles, start by sketch the trapezium, which has one pair of parallel sides. Next, divide the trapezium into three triangles by drawing two lines from the top base to the bottom base, ensuring that they meet at a point along the bottom base. You can vary the angles and positions of these lines to create different shapes of triangles within the trapezium. Finally, shade or color the triangles as desired for visual distinction.
a pentagonal pyramid it has five triangular sides that all meet at a point at the top. the base is a pentagon
A pyramid
orthocenter
Four of them