Find the number of edges in octahedron.

The picture shows the shape of a boiler. Total height of the boiler is $12$ metres and the diameter is $6$ meters, height of the cylindrical part is $6$ meters.

What is the height of the cone?

The figure of a square sheet paper is shown below. Length of one side of the paper sheet is $36 \mathrm{cm}$ and $AB=10 \mathrm{cm}$. The shaded portion is cut out and folded into a square pyramid. If the length of the base of the pyramid is $k \mathrm{cm}$, find $k$.

Name the polyhedron that can be made by folding each net:

State whether the following is true or false.

A cube has twice the number of edges as a tetrahedron.

Name the polyhedron that can be made by folding each net:

How many edges are there in a cuboid.

Write down the number of faces of cuboid.

The number of edges in a square pyramid is:

Name the polyhedron that can be made by folding each net:

A square pyramid has $6$ faces.

The solid that is not a regular polyhedron among the following is