A ratio is one where you describe the relationship between 2 numbers. It is a statement that can be reduced or simplified.
And a proportion is nothing but 2 ratios that have values that is equal. Unlike a ratio, the proportion can be worked out and solved. And when you say that a proportion is 2 ratios that have values equal to other, let’s take this proportion:
5/10 is equal to 1/2
Hence, to solve a proportion, you need to have the knowledge of both ratios and proportion together. If we want to express 4 quantities (a,b,c,d) in a proportion then remember that a:b should be equal to c:d
a:b = c:d or a/b = c/d
When you write a proportion like this, a and d are called the extremes of the proportion whereas b and c are called as the middle terms of the proportion.
With Proportions, we can easily solve percent problems. Say for example, if the problem is to find out 25% of 180, we can write it like:
x / 180 = 25/100
Now we need to multiply the opposite corners, hence 25 x 80
X = 180 X 25 / 100
x = 4500/100
x = 45
Hence the answer here is 45.
This can also be achieved by another method where you can:
= 180 X 25 / 100
= 180 x (25/100)
= 180 * 0.25
1. Find the unknown value in the proportion: 2 : x = 4 : 8?
Let’s first convert the proportion into a fractional form,
2/x = 4/8
To solve the proportion, multiply the values across like:
2×8 = 4x
4x = 2 x 8
4x = 16
x = 16/4
So x = 4
2. If a car is driving at a speed of 2 miles per hour, how far will it travel in 5 hours?
Set up the ratio:
2 miles / 1 hr = x miles / 5 hr
2 * (5) = (1) * x
10 miles = x
3. What is 25 percent of 50?
Since 50 is equal to 100%, we must figure out what is 25%. Set up the ratio as the following:
50 / x = 100 / 25
50 * 25 = 100 * x
Divide each side by 100
(50 * 25) /100 = 100/100 * x
x = 12.5