Finding the Original Amount and Amount of Change Using Proportions and Equations

This video tutorial teaches how to find the original amount and the amount of change given the percent change and final amount using proportions and equations. It uses a practical example of calculating the pre-tax price of a couch and the sales tax from a given final price. The lesson reviews solving proportions and equations, emphasizing the difference between percent change and the actual amount of change. It provides two methods: using proportions and using equations, to solve for the original amount and the tax.

Explain the difference between the percentage of change and the amount of change.

What is the original amount of the couch before the sales tax was added?

How much was the sales tax on the couch?

What is the final amount Chris offered for the couch including tax?

What method can be used to find the original amount when given the final amount and the percentage of tax?

Describe the process of using proportions to find the original amount in this scenario.

How do you convert a percentage to a decimal for calculations?