Sigrid

a piece of wire is 20 cm. long. it is cut into pieces, each of which is then bent to form a square. the total area of the two squares is 13 sq. cm. How long is side of each square?

A square piece of cardboard is to be used to form a box without a top by cutting off squares, 5cm on a side, from each corner and then folding up the sides. if the volume of the box must be 320 sq. sm, what must be the length of a side of the cardboard?