Henrico County Public Schools

Find the Percent

Created by Steven Lapinski using the Compass and Ruler (C.a.R.) program.


Try solving these problems using the Part and Whole sliders.
1. 17 is what percent of 51?
2. What percent of 75 is 36?
3. If there are 80 students and 16 are late to school, What percent of the students are late?


Solving Percent Problems

To solve percent problems, one begins by using a number line to help write a proportion. The next step is solving the proportion for the missing term. Remember that a percent is always some part of 100. We can set up a proportion where each side is a ratio. The following examples demonstrate using a number line and proportion to solve percent problem.


Example 1: 18 is what percent of 72? This can be rephrased as “18 is what part of the whole - 72?” Arrange the numbers along a number line (see the figure on the right) and place the part above the x% and whole above the 100%. Write the proportion and follow the steps on the far right. Example 1:

Proportional Percent Calculator

Enter the values from your proportion. Place an x for the unknown in the appropriate box, then click on Calculate.
Part
Whole

=

%
100 %

 

Original Script, LeMieux, 2001
Enhanced, Lapinski, 2003

Percent Problems

The correct answer is provided to determine if you placed the numbers appropriately.

Example 1: 25 is what percent of 125?
The correct answer is provided to determine if you placed the numbers appropriately.
This can be rephrased as “25 is what part of the whole - 125?” Write the proportion. (Answer: 20%)

Problems:
3 is what percent of 15? (Answer: 20%)
What percent is 60 of 75? (Answer: 125%)
80 is what percent of 30?

LESSONS

Find Percent

Find the Whole

Find the Part

Increase/Decrease

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