Middle School Math proportions

Introduction to middle school math proportions:

A proportion is called an equation with two ratios on each side (these two ratios are equal). It is denoted by the symbol ‘::’ or ‘=’ to equate the two ratios.  If two ratios are not equal, then the given values are not in proportion. In a proportion, the four terms (quantities) involved. First and fourth terms are known as extreme terms. Second and third terms are known as middle terms.

For example proportion:   50: 100:: 2 : 4;

50, 100, 2, 4 are the four terms. 50 and 4 are the extreme terms. 100 and 2 are the middle terms.

Steps to solve proportions:

Solving proportions is the process of setting the two fractions equal to each other, cross-multiplying, and solving the resulting equation.

When one of the four numbers in proportions is unknown, using the cross product we have to find the unknown number. This is called solving the proportions. Letters or Question marks are commonly used in place of the unknown number.

Here, we are going to see some of the middle school math proportions problems.


Example on middle school math proportions


The following are the middle school math proportions problems:

Example problem 1:

In 2005 the number of men enrolled was 194 while women to men enrolled in chemistry are 78: 162 in 2004. How many women were enrolled in chemistry in 2005?

Solution:

Let x is the unknown number of women

78: 162 = x: 194

Cross multiply,

78 * 194 = 162 x

15132 = 162 x

Divide by 162 on both sides

93.4074 = x

So, the women were enrolled in chemistry in 2005 is 93.4074.Approximately it is 93 members. I like to share this Adding Mixed Fractions with you all through my article.



Few more example on middle school math proportions

Example problem 2:

Margret ran 100 meters in 15 seconds. How long did she take to run 1 meter?

Solution:

In 15 seconds Margret ran 100 meters. so x is the unknown.

100/15=1/x

Cross multiply and we get:  100x = 15

Divide both sides by 100 and we get

x = 15/100

x=0.15seconds

So, she takes 0.15 seconds to run 1 meter.

Example problem 3:

In a school, 476 students ride their bicycle to school. If this number is 70% of the school enrollment, then how many students are enrolled?

Solution:

476/y=70/100

Cross multiply and we get:  70y = 47600

Divide both sides by 70 and we get:  y = 680

There are 680 students enrolled in that School.