pyramid
A pyramid
This would be a triangular prism.
It doesn't exist. The least number of sides for a 3-D shape only made of triangles is 4.
Two three-dimensional shapes that have at least one triangle as a face include a triangular prism and a pyramid. In a pyramid, the outer faces are triangles, and they come together at one point. A triangular prism is a type of prism with a triangular base.
You need at least four triangles, or at least three trapeziums. Or two triangles and one trapezium.
It is 8 triangles
Both have at least one hexagonal face (base). Both have six faces that are topologically equivalent (either rectangles, or triangles).
All triangles need at least two acute angles
Two Isosceles triangles.__ ^/ / / |/ / / |V --
only right tringles or HL triangles have at least 1 right angle
equilateral triangles and isosceles ones
The smallest number of triangles that you could divide a nonagon into is seven.