Answer:
perimeter of square = 35.78 cm
Step-by-step explanation:
cut the rhombus into 4 triangles along the diagonals
each triangle has a base of 5 and a height of 10 cm
area of one triangle = 1/2(4)(10) = 20 cm^2
4 triangles = area of rhombus = 80 cm^2
then the square has an area of 80 cm^2 also
side^2 = 80 cm^2
side of square = 8.94 cm
perimeter = 8.98 x 4 = 35.78 cm