Did you drive to work today? If you did, you used a ratio. Driving 30 miles per hour involves a ratio or proportion of two numbers. It can be written as a fraction, , or the way we most commonly see it: 30 mph. Let’s start the discussion this week by identifying other proportions we see in our everyday lives. Think of an example of a proportion you use in your life. List the proportion, explain its meaning, and don’t forget to include its fraction equivalent.
An example of a proportion used almost everyday is when a discount the price of a product being purchased has to be determined.
This is usually given a percentage which is the amount reduced if the price were 100. For instance a 10% discount implies that the product would cost 90 if its original price was 100.
If there is a 10% discount on a product, to estimate the discount D if the initial cost is X use the proportion D: X = 10/100
=> D = X*(10/100) = 0.1*X