A ratio gives the relative sizes of two sets but not the actual numbers of objects in those sets.
There are 21 students in a classroom that consists of 3 males and 18 females. What is the ratio of males to females?
Answer: 3/18 = 1/6, (can be reduce to 1/6 in lowest terms), 1 to 6, or the most common way to write a ratio, 1:6
A proportion is a part considered in relation to the whole.It's an equality of ratios. Each ratio gives rise to many pairs of equal ratios.
For any two ratios a/b and c/d, a/b = c/d - proportion
If the ratio of teachers to students in a school is 1 to 18 and there are 360 students, how many teachers are there?
1 teacher = x teachers
18 students 360 students = 20 Teachers
We know that the numerator and denominator of 1/18 must be multiplied by the same number to result in an equal fraction. Since the denominator of 1/18 must be multiplied by 20 to get 360 (360/18=20),
So the number of teachers is 20.
Another example of how you could solve a proportion-
Ratios and Proportions - This website helped me understand the definitions of ratios and proportions.