Concept of permutations and combinations can be applied to various questions involving geometrical shapes.  Some of the commonly asked questions are:

Number of triangles using \( n \) straight lines or \( n \) points

Number of intersection points by \( n \) straight lines

Number of straight lines that can be formed using \( n \) points

Number of squares in a grid

Number of rectangles or parallelogram in a grid

Number of diagonals in a polygon 

Maximum number of regions formed by \( n \) intersecting lines.