What is a ratio?
Example: Rogerião and Claudinho walk with their dogs. Rogerião weighs 120kg, and his dog, 40kg. Claudinho, in turn, weighs 48kg, and his dog, 16kg.
Notice the ratio between the weight of the two boys:
Notice now the ratio between the weight of the dogs:
We find that both reasons are the same. In this case we can say that equality is proportion. Like this:Proportion It is an equality between two reasons. Next: Elements of a Aspect Ratio