Equivalent Ratios-Proportions
A proportion is a name we give to a statement that two ratios are equal.
When two ratios are equal, then the cross products of the ratios are equal.
a●d=c●b
5 ● 30 = 10 ● 15
150 = 150 (true)
Multiply the diagonals
and
determine if
the statement is true.
If the statement is true
then the ratios are
equivalent or
proportional
Making an Equivalent Ratio
There are 810 Calories in 3 scoops of Vanilla Ice Cream. How many Calories are there in 7
scoops of ice cream?
Write 2 equivalent ratios.
810 ● 7 = 3 ● x
Make sure your labels match on each side of
the equal sign
5670 = 3 ● x
Cross Multiply
5670 ÷ 3 = x
Divide by the number next to missing number
1890 calories in 7 calories