3D is the three dimensional shapes in geometry which is a solid and bounded by length, breadth and height
like the room has length, breadth as well as height of the room is a 3D shapes, book, box, pencil, pots all are
the example of 3D shapes.
Examples of 3D shapes: -
A pyramid is a solid bounded by plane faces; one of its faces is a polygon of any number of sides and the
other faces are triangles whose bases are the sides of the polygon and which meet at a common point
outside the plane of the polygon.
The plane face which is a polygon, is called the base of the pyramid and the triangular faces are its lateral
faces. The common point at which the lateral faces meet is called its vertex. The straight line in which
adjacent faces intersect called the edges (or lateral edges) of the pyramid. The perpendicular distance from
the vertex to the plane of the base is called the height (or altitude) of the pyramid.
The area of the slant surface of the right pyramid= (1/2 ) x perimeter of the base x slant height
· Area of the whole surface of the right pyramid =area of its slant surface + the area of its base.
· Volume of the right pyramid= (1/3) x area of the base x height.
A prismis a solid bounded by a number of plane faces; its two faces, called the ends, are congruent parallel
plane polygon and other called the side faces.