In geometry, the pentagonal pyramid is one of the Johnson solids (J₂). Like any pyramid, it is self-dual. It can be seen as the "lid" of an icosahedron; the rest of the icosahedron forms a gyroelongated pentagonal pyramid, J₁₁.

The 92 Johnson solids were named and described by Norman Johnson in 1966.

More generally an order-2 vertex-uniform pentagonal pyramid can be defined with a regular pentagonal base and 5 isosceles triangle sides of any height.

External link

• Johnson Solid -- from MathWorld

Pyramids and bipyramids | Self-dual polyhedra | Prismatoid polyhedra | Johnson solids

正五角錐