Exercise 4 Page 147

Let's start by recalling that a percent of change is a ratio that compares the change in quantity to the original amount. If the original quantity is increased, then it is called a percent of increase. If the original quantity is decreased, then it is called a percent of decrease. To determine the percent of change, we can use the following formula. Percent of change =Amount of change/Original amount In this case, the original quantity is 125 centimeters, and the new quantity is 87.5 centimeters. We can find the amount of change by subtracting the less value from the greater one. Amount of change = 125cm - 87.5cm = 37.5cm Now let's use the formula to find the percent of change. To make the math easier, we can ignore the units for now.

To write the decimal as a percent, we need to move the decimal point two places to the right and write the percent symbol.

We found that the percent of change is 30 %. Finally, let's state whether the percent of change is an increase or a decrease. To do so, we need to compare the original quantity with the new quantity. ccc Original quantity & & New quantity [0.5em] 125cm & > & 87.5cm Since the new quantity is less than the original quantity, this is a percent of decrease.