A squares area is a side squared so 8^2= 64, and it is also shown that a side of the square is the base of the parallelogram. The area of a parallelogram is b*h so (square side)(8) * height(5)= 40.
Since a parallelograms opposite sides are congruent, 8+8=16, and the other two sides need to be congruent and equal to 40-16(24), therefore the sides are both 12.
Then to calculate the perimeter just count up the side lengths, 8+8+8+12+8+12=56
