Calculating Percent of Increase and Decrease Using Proportions

The video tutorial explains how to calculate the percent of change using proportions. It begins with an introduction to the concept of percent change and proportions, followed by an example involving population growth in Urbantown. The tutorial provides a detailed calculation of the percent increase and addresses common misunderstandings students may have when setting up proportions. The lesson emphasizes the importance of using the original amount as the denominator in calculations.

What is a proportion in the context of calculating percent of change?

• A statement showing two ratios are equal through division

• A statement showing two ratios are equal through subtraction

• A statement showing two ratios are equal through multiplication by a scale factor

• A statement showing two ratios are equal through addition

In the example of Urbantown, what was the original population in 2012?

• 14,000 people

• 2,500 people

• 12,000 people

• 16,500 people

How is the percent of increase calculated in the Urbantown example?

• By dividing 2,500 by 120

• By dividing 2,500 by 14,000

• By dividing 12,000 by 2,500

• By dividing 14,000 by 12,000

What is the simplified fraction used to calculate the percent of increase in the example?

• 240 divided by 10

• 240 divided by 12

• 250 divided by 10

• 250 divided by 12

Why is it important to use the original amount in the denominator when calculating percent of change?

• To ensure the new amount is larger

• To compare the change to the starting amount

• To use the largest number available

• To make the calculation easier