I have an old thermostat and just bought a Honeywell RTH230B1006. I have four wires, 1 red, 1 blue, 1 yellow, and 1 white. The back of the new thermostat says Rh, Rc, W, Y, and G. Where does each wire go? Thank you!

I had one of the older ones that are circle. It is still hooked up but can not tell which lines is going where. The white wire isn't hooked up to anything. That may have happened when I took it off the wall. I will have someone look at the furnace. Thank you.