Final answer:
The maximum number of points of intersection of 4 rectangles is 24.
Step-by-step explanation:
The maximum number of points of intersection of 4 rectangles can be found by considering all possible pairs of rectangles and determining the number of points at which their sides intersect.
When two rectangles intersect, they can have up to 4 points of intersection. So, for 4 rectangles, there can be a maximum of 4 points for each pair of rectangles.
Since there are 4 rectangles, there are ${inom{4}{2}} = 6$ possible pairs. Therefore, the maximum number of points of intersection is $6 imes 4 = 24$.