Arhombus and a square have one and the same side of 6 cm. the area of the rhombus is 4/5 of the area of the square. find the height of the rhombus. i got stuck repeatedly, so hoping someone out there can me out.. if not, then, oh well.

You will find the area the square and then find out what 4/5 of that area is.

A = bh
     6 cm x 6 cm 
A = 36 square cm

4/5 of 36 square cm
4/5 x 36
28 4/5 square cm

The area of the rhombus is 28 4/5 square cm.  Use this to solve for the height of the rhombus.

A = bh
28 4/5 = 6 x h
6            6
h = 4 4/5 cm

The height of the rhombus is 4 4/5 cm.