Heptagonal Prism
A cuboid or a pyramid with a heptagonal base are two possibilities.
A heptagonal prism gas 21 edges.
There are many possible shapes. For example, a heptagonal pyramid, a hexagonal prism, a rectangular dipyramid.
Heptagonal is an adjective, not a noun! The answer will depend on whether you mean a heptagonal pyramid, a heptagonal bipyramid, a heptagonal prism or whatever.
Heptagonal is an adjective: the answer depends on the noun that it refers to. A heptagonal pyramid, a heptagonal dipyramid or a heptagonal prism or some other heptagonal shape?
a heptagonal pyramid
A heptagonal pyramid.
It could be a heptagonal prism.
Heptagonal pyramid * * * * * No. A heptagonal pyramid has 8 vertices. You need a hexagonal pyramid or a pentagonal dipyramid for 7 vertices. Or, in 2d, a heptagon.
Heptagonal Prism
heptagonal prism
A cuboid or a pyramid with a heptagonal base are two possibilities.
A heptagonal prism gas 21 edges.
Strictly speaking, no. Perhaps you can refer to it as a heptagonal shape?
There are many possible shapes. For example, a heptagonal pyramid, a hexagonal prism, a rectangular dipyramid.
Heptagonal is an adjective, not a noun! The answer will depend on whether you mean a heptagonal pyramid, a heptagonal bipyramid, a heptagonal prism or whatever.