A hexahedron.
Which may also be known as a pentagonal pyramid.
Although it could also be a horizontal pentagon with a vertical pentagonal band formed by ten triangles (aternately facing up and down), topped by five trianles meeting at an apex: a 16-faced polyhedron. Or, of course, it could have two bands of vertical facing triangles - making a 26-hedron, etc.
it's a pyramid with 5 sides.
A solid figure with a pentagon as its base and triangular faces is called a pentagonal prism. In this 3D shape, the two pentagonal bases are parallel and connected by five rectangular lateral faces. However, if you specifically mean a solid with a pentagonal base and triangular faces that converge at a single point, then it is known as a pentagonal pyramid.
Triangular based pyramid
triangular cone
a triangular prism.
pyramid
pentagonal pyramid
it's a pyramid with 5 sides.
A pentagon-based pyramid
It is a pyramid
A triangular prism.
Four triangular faces.
A Triangular Prism
Triangular based pyramid
Triangular prism.
a triangular prism!
triangular cone