$A$ polygon has $54$ diagonals. Then,the number of its sides is

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?

The sides $AB, BC, CA$ of a triangle $ABC$ have respectively $3, 4$ and $5$ points lying on them. The number of triangles that can be constructed using these points as vertices is

Two squares are chosen at random on a chessboard. The probability that they have a side in common is:

Out of $n$ points in a plane,$p$ points are collinear. (No three of the remaining points are collinear). The number of lines that can be drawn passing through these points is:

The number of parallelograms that can be formed from a set of $4$ parallel lines intersecting another set of $3$ parallel lines is: