Ratios and Rates
Ratios and Rates
Ratios and Rates
ratio – a comparison of two
numbers by division written
in several different forms.
That
This
That
This
Ratios and Rates
rate – a ratio that compares
different kinds of units by
division to obtain a unit rate
or rate per unit.
Ratios and Rates
The order of the numbers in
a ratio should match the
order of the words in a ratio.
apples to oranges
2 to 3
Ratios and RatesRatios can be written in
several different ways.
3 to 1
3 : 1
3/1
red to white
Ratios and Rates
Ratios can show comparisons
between:
part to part
red to green
1 to 2
green to red
2 to 1
Ratios and Rates
Ratios can show comparisons
between:
part to whole
red to whole
1 to 3
green to whole
2 to 3
Ratios and Rates
Ratios can show comparisons
between:
whole to part
whole to red
3 to 1
whole to green
3 to 2
Ratios and Rates
Compare octagon to all shapes
1 to 8
1 out of 8 1 : 8
1/8
Ratios and Rates
Compare all shapes to trapezoid
8 to 1 8 : 1 8/1
Ratios and Rates
Compare pentagons to hexagons
2 to 3 2 : 3 2/3
Ratios and Rates
Give each ratio in three forms.
8 roses out of 24 flowers
8 to 24 8 : 2424
8
3 dogs out of 12 animals
3 to 12 3 : 1212
3
Ratios and RatesA ratio in fraction form can be
expressed in simplest form by
dividing the numerator and
denominator by a common
factor.
24
8 ÷ 8
÷ 8
=
3
1
12
3 ÷ 3
÷ 3
=
4
1
Ratios and RatesTo express a ratio as a rate per
unit, write the ratio as a fraction
and then divide the numerator
by the denominator.
395 miles in 5 hours
5
395=
79 miles
per hour
miles
hours 1
? miles
hours
Ratios and RatesExpress each ratio as a rate.
5 inches of rain in 30 days
30
5=
6
1inch of rain per day
120 words in 3 minutes
3
120=
40 words
per minute1
? wordsper minute
÷ 5
÷ 5