A tinsmith wants to make a small windowsill planter from a 40cm×22cm sheet of copper. She’ll form it by cutting equally sized squares from each of the four corners of the sheet, folding up the resulting flaps to form the sides of the planter, and then soldering the four vertical edges. If she wants the ratio of the planter’s length to height to be 3, what will be the ratio of its length to width? Write the exact answer. Do not round.