What is ratio?

Understanding Ratio Tables
Fill in the blanks in the following ratio table.

x y

4

8 14

21
Part-to-part Ratio Vs. Part-to-whole Ratio
There are 14 boys and 16 girls in a particular class.
1. Find the ratio of boys to girls.
2. Find the ratio of boys to the whole class.
Charlie bought 2 Superman action figures and they are 4.4 cm and 9 cm tall respectively. What is the ratio of the height of the smaller figure to the larger figure?
Evaluate Ratios Involving Unit Conversion
Betty and Mary participated in a 400 m sprint. Betty finished it in 1 min 40 sec while Mary finished it in 2 min 15 sec. What is the ratio of Mary's time to Betty's time?
Determine the Scale of a Map (Ratio)
The distance between two cities on a map is 4 cm. If the real distance between the cities is 28 km, what is the scale of the map?
A Tyrannosaurus (a dinosaur) is 12.3 m in length. If a model was built using the ratio 1:15, what is the length of the model?
Analyze Ratios of 3 Objects
A bank wants to maintain the managers, analysts and tellers in the ratio 2:5:18. If 15 analysts were hired, how many managers and tellers should they hire?

In this lesson, we will learn:

Notes:

A ratio shows the relative values of two or more objects
A punctuation mark colon (:) or the word "to" is used to separate the values.
A ratio can be expressed as a fraction, which can be further converted to a decimal or a percentage.
A ratio should always be in its simplest form (no common factors).
The values in a ratio should always be integers if possible.
A ratio can be scaled up/down by multiplying/dividing the ratio numbers by the same value. This process is called scaling, and the value used for scaling is called the scale factor.
There are two types of ratio:
- Part-to-part (comparing one part to another)
- Part-to-whole (comparing one part to the whole)