The amount of cake required for 80 people can vary depending on several factors, such as the serving size and the type of event. However, as a general guideline, you can use the following estimates:
Party-sized slices: If you're serving party-sized slices of cake, which are typically smaller, you can estimate that one 9-inch round cake or a 9x13-inch rectangular cake can serve approximately 20 people. Therefore, for 80 people, you would need around four 9-inch round cakes or four 9x13-inch rectangular cakes.
Larger slices: If you're serving larger slices of cake, you may need more cake to accommodate the portion sizes. In this case, you can estimate that one 9-inch round cake or a 9x13-inch rectangular cake can serve approximately 10 to 12 people. For 80 people, you would then need around eight 9-inch round cakes or eight 9x13-inch rectangular cakes.
Keep in mind that these estimates are general guidelines and can vary depending on the preferences of your guests and the overall menu of your event. It's always a good idea to consider the context and specific requirements of your occasion to ensure you have enough cake for everyone.