Proportions

Proportions

Everyone has somehow seen and used proportions before, such as baking recipes and maps. Proportion is basically another way to say two ratios or rates are equal. We can represent proportions in two ways: in the form of fraction (a/b = c/d) and using a colon (a:b = c:d).
Basic concepts: Ratios,

Lessons

  • Introduction
    How to do cross-multiplication?

  • 1.
    Find the missing value.
    a)
    34=9\frac{3}{4} = \frac{9}{{}}

    b)
    5=3036\frac{5}{{}} = \frac{{30}}{{36}}

    c)
    2149=7\frac{{21}}{{49}} = \frac{{}}{7}

    d)
    5=1830\frac{{}}{5} = \frac{{18}}{{30}}


  • 2.
    A butter cookie recipe calls for 250 g of butter and 170 g of sugar. How much sugar is needed if there is 625 g of butter?

  • 3.
    The scale of a map is 1.5 cm to 30 km. What is the actual distance between two places which are 33.5 cm apart from each other on the map?

  • 4.
    There is 54 g of fruits in a smoothie. If the ratio of strawberry and blueberry in the smoothie is 5:4, how much of each fruit is there in the smoothie?

Do better in math today
5.
Introduction to Ratios, Rates and Percentages
5.1
Ratios
5.2
Rates
5.3
Proportions
5.4
Representing percents
Don't just watch, practice makes perfect.