Final answer:
Use a wattmeter to measure the power consumption of each appliance to discover if your guesses about their power ratings are correct.
Step-by-step explanation:
One way to discover if your guesses about the power ratings of appliances in a room are correct is to use a wattmeter to measure their power consumption. A wattmeter is a device that measures the power used by an electrical appliance. By connecting the wattmeter to each appliance and recording the power readings, you can compare them and determine if your guesses about the highest and lowest power rating appliances were accurate.