Fish Tank Task

You are getting a new fish tank and combining both your old tanks that are square prisms into a new one that is the shape of a cube. In order to keep your fish from going into shock, you have to pour both tanks into the new one so that the old tanks meet at a right angle. If your new tank holds 125 cubic feet of water? What are the dimensions of your original tanks so that the new tank is filled perfectly?

Information: Fish Tank Task