# 8.1.11 Calculator Exploration: Using Percentages

The calculator can be accessed on the left-hand side bar under Toolkit.

In the following exploration, you will use the calculator for calculations involving percentages.

## Finding a Percentage of a Number

Suppose that residents in a town are asked their views on a proposed development of a wind farm near the town. The local paper says that 450 people voted, with 54% in favor of the proposal, 36% against the proposal and 10% saying that they were undecided. How many people were in favor of the proposal?

To find the number of people who were in favor, you need to find 54% of 450. The calculation is: .

Enter this into the calculator and you will see:

So, 243 people were in favor of the proposal.

The percent key is useful here. Enter .

The calculator shows:

Again, you can see that 243 people were in favor of the proposal.

### Activity: Methods for Finding Percentages

Now it’s your turn. Try both methods (first, entering the percentage as a fraction, and second, using the percent key) to find the number of people who were against the proposal. Then find the number of people who were undecided about the proposal. (Try this calculation without using the calculator.)

#### Comment

For the first method, enter the percentage as a fraction, then multiply by 450. For the second method, enter the percentage followed by the percent key, then multiply by 450.