If all the sides of a parallelogram are equal, then it is a rhombus. We know that the diagonals of the rhombus bisect each other at right-angle. Let the diagonals are d1 and d2, then given that
d1
d2
=
1
2
and d1+d2=12 From above two, d1=4,d2=8 Now, area of parallelogram, A=