i know it's rude and pretentious and maybe stupid to ask such question but, i would like to know the reason why in geometry the area of a parallelogram follows this formula :
$ Base \times Height $
and not this one :
$ Base \times Side $
I saw this method which consists of transforming our figure into a rectangle by moving the black one to the right, and that seems logical to me, but why not adopt the second rule, all the horizontal points multiplied by the vertical ones ?
PS : I found the same Visualizing the Area of a Parallelogram, but was unconvinced by the answers