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2. Oblique Prism: An oblique prism
is a slanted prism whose base and Remember
lateral faces are not proportional. Not all oblique prisms are rectangular.
A parallelopiped is an oblique prism
Naming Prism whose base is a parallelogram.

Prisms are named according to their bases.
1. Triangular Prism: A prism whose bases are triangles and is
bounded with three rectangular sides.
Lateral face
It has 2 triangular bases and 3 lateral rectangular faces.
So, it has 6 vertices, 9 edges and 5 faces.

2. Rectangular Prism: A prism whose bases and faces are
rectangles. It is also called a cuboid or rectangular solid.
Lateral
It has 2 rectangular bases and 4 lateral rectangular faces. face

So, it has 8 vertices, 12 edges and 6 faces.

3. Square Prism: A prism whose bases are squares and lateral faces
are squares/rectangles.
It has 2 square and 4 lateral faces.

So, it has 8 vertices, 12 edges and 6 faces.
4. Pentagonal Prism: A prism whose bases are pentagons, and
lateral faces are parallelograms (rectangles).

So, it has 10 vertices, 15 edges and 7 faces.

Note: If the base of a prism is a polygon of n sides, then it has (n + 2) faces, 2n vertices and 3n edges.
Pyramid

A polyhedron whose base is a polygon and lateral faces are triangles with a common vertex is
called a pyramid. Terms associated with a pyramid are:
Apex: A common point where edges of triangular lateral faces meet. Lateral
Axis: The line segment joining the apex and the centre of the base. face

Height: The perpendicular length from the apex to the base of a pyramid.

Lateral Faces: The faces other than the base
Naming Pyramids

Pyramids are named according to their bases.

1. Triangular Pyramid: A pyramid that has a triangular base and three
triangular lateral faces is called a triangular pyramid. (It is also known as
a tetrahedron. If all the three triangular faces are equilateral, then such a
pyramid is called a regular tetrahedron). It has 4 vertices, 6 edges and 4
triangular faces.

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