Final answer:
The main types of taxes in the U.S. are progressive taxes, where high earners pay a higher percentage of their income, and proportional taxes, where everyone pays the same percentage regardless of income.
Step-by-step explanation:
The two main types of taxes in the United States are progressive taxes and proportional taxes. A progressive tax is a system where the rate of taxation increases with the income level of the person or entity being taxed. An example of a progressive tax is the federal income tax, where those with higher incomes pay a greater share of their income in taxes compared to those with lower incomes. On the other hand, a proportional tax, also referred to as a flat tax, has a constant tax rate regardless of income. An example is the payroll tax for Medicare, where everyone pays the same percentage of their income.