Mark four points $A, B, C$ and $D$ in your notebook such that no three of them are collinear. Draw all the lines which join them in pairs as shown in Figure.

How many such lines can be drawn?

Mark four points $A, B, C$ and $D$ in your notebook such that no three of them are collinear. Draw all the lines which join them in pairs as shown in Figure.

Write the names of these lines.

Mark four points $A, B, C$ and $D$ in your notebook such that no three of them are collinear. Draw all the lines which join them in pairs as shown in figure.

Name the lines which are concurrent at $A$.

A page of a book is a physical example of a _____.

An inkpot has both              surfaces.