If a polygon has $44$ diagonals,then it has ...... sides.

The number of diagonals in a regular polygon of $100$ sides is

If the number of diagonals of a regular polygon of $n$ sides is $104$,then $n=$

In a tournament with five teams,each team plays against every other team exactly once. Each game is won by one of the playing teams and the winning team scores one point,while the losing team scores zero. Which of the following is $NOT$ necessarily true?

Six '$X$'s have to be placed in the squares of the figure such that each row contains at least one '$X$'. In how many different ways can this be done?

Out of $18$ points in a plane,no three are in the same straight line except five points which are collinear. The number of $(i)$ straight lines and $(ii)$ triangles which can be formed by joining them is: