A closed rectangular box has volume 28cm3. What are the lengths of the edges giving the minimum surface area? lengths =

For the surface of rectangle to be minimum the the dimensions must be equal. Let the length=width=height=x cm
thus the volume will be:
x×x×x=28
x³=28
x=∛28
x=2√7 cm
thus the dimensions are such that length=width=height=2√7