4-sided equalateral be a ROMBUS...squashaed square
all 4 sides the same
draw 1 diagonal...2 sides the same, so it be isosaleez triangel ,
so base angels the same
the diagonal make 2 triangels with 1 kommon side & other 2 sides the same
so em 2 triangels the same
that meen the diagonal bisekted the angels at the 2 ends
draw other diagonal & it bisekt the other 2 angels & form 2 idetikal triangels
with both diagonals, yu hav 4 triangels...all hav 1 side=side av rombus=the same
all hav 1 kommon side
all hav 1 angel=weer 2 lines kross, so angels on 2 sides av the kros =the same
Thus, all 4 triangel the same
Thus, 1 side=half av 1 diagonal & other side=half av other diagonal
Thus diagonals bisekt eech other