Proportion Scenarios

Types of proportion scenarios

There are usually two types of proportion scenarios:

• find a missing quantity (given a ratio of two quantities and one of the actual quantities)
• compare two proportions (not covered here)

You can solve 'missing quantity' proportion questions using any of the following methods:

1. writing and solving a proportion equation (an algebraic method)
   or
2. finding the equivalent ratio for one unit then multiply by the required number of units (the unitary method -- a non-algebraic method)
   or
3. first creating a table of values then building up or down to the required number of units by multiplying and/or dividing (another non-algebraic method).

Try these questions to test your understanding. You may want to review one or more of the methods mentioned above by following the links.

If $1000$ lines of code can be executed in $15$ seconds, how many lines of code can be executed in $9$ seconds?

Check Answer

A rectangular image is enlarged so that its length changes from $6$ cm to $80$ cm. If the original width of the image is $15$ cm, what is the width of the enlarged image in cm if the image stays in the original proportion (that is it is enlarged without distortion)?

Check Answer

Suppose $18$ flower stems cost $\$15$. How much would you pay for $21$ flower stems? Do not include the \$ sign in your answer.

Check Answer

For more practise of your proportional reasoning skills try these questions.