scalene, have you ever been to school?
Pyramid.
a square
Rhombus Hexagon Octagon Nonagon Decagon all have 7 letters
heptagon
There is no such polyhedral shape since the numbers do not satisfy the Euler characteristic.
Pyramid.
A Pyramid is a 7 lettered 3D shape with triangular faces.
Pyramid
A triangular prism has 5 faces. Pentagonal prisms and hexagonal pyramids have 7.
A pentagonal prism has 7 sides : 5 side faces and 2 bases.However, if all sides of the prism are considered faces, a shape with5 total faces including the 2 bases is a triangular prism.
A heptahedron has 7 faces, including 6 triangular faces and one hexagonal.
There are a number of possible 7-sided polyhedra. Three that come immediately to mind are: a hexagonal pyramid, a pentagonal prism, a "stretched" triangular pyramid (triangular base, rectangular sides, and then triangular faces meeting at an apex).
An octahedron is a closed 3-d shape with 8 polygonal faces. There are 257 topologically different convex octahedra. The number of triangles will depend on which one of the 257 shapes you have in mind:All 8 faces of a quadrilateral based bipyramid will be triangles.A heptagon based pyramid has 7 triangular faces.A hexagonal prism has none.
A heptagon.
Heptagon
A heptagon.
A hexagonal pyramid.================A pyramid with 7 faces has a base plus 6 triangular sides, so is called a hexagonal pyramid.