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Transcript Document

Ratios
Ratios
ratio – a comparison of two
numbers by division written
in several different forms.
Ratios
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
Ratios can be written in
several different ways.
red to white
3 to 1
3:1
3/1
Ratios
Ratios can show comparisons
between:
part to part
red to green
1 to 2
green to red
2 to 1
Ratios
Ratios can show comparisons
between:
part to whole
red to whole
1 to 3
green to whole
2 to 3
Ratios
Ratios can show comparisons
between:
whole to part
whole to red
3 to 1
whole to green
3 to 2
Ratios
Compare octagon to all shapes
1 out of 8
1 to 8
1:8
1/8
Ratios
Compare all shapes to trapezoid
8 to 1
8:1
8/1
Ratios
Compare pentagons to hexagons
2 to 3
2:3
2/3
Ratios
Give each ratio in three forms.
8 roses out of 24 flowers
8 to 24
8 : 24
8
24
3 dogs out of 12 animals
3 to 12
3 : 12
3
12
Ratios as Decimals
A ratio can be turned into a
decimal by using division.
20 in. out of 25 in.
0 .8
25 20 . 0
20 0
0
Ratios as Decimals
9cm : 12 cm
0 .7 5
12 9 . 0 0
84
60
60
0
Equivalent Ratios
Ratios can be put in simplest
form by dividing by the Greatest
Common Factor (GCF).
6 in. to 2 in.
GCF = 2
÷2
÷2
3 in. to 1 in.
Equivalent Ratios
100 yd : 85 yd
÷5
÷5
20 yd. to 17 yd.
GCF = 5
Equivalent Ratios
A ratio in fraction form can be
expressed in simplest form by
dividing the numerator and
denominator by a common
factor.
8 ÷8 1
=
÷
8
3
24
3 ÷3 1
=
12 ÷ 3 4
Equivalent Ratios
If not specified that simplest
form is required, equivalent
ratios can be created by
multiplying by the same
number.
6 x 3 18
=
x
3
63
21
4
9
20
=
x5
45
x5
Equivalent Ratios
30 m : 10 m
x 10
x 10
300 m. to 100 m.
4 balls to 12 bats.
x4
x4
16 balls to 48 bats
Equivalent Ratios
If two fractions are given, how
do you test to see if they are
equivalent?
5 x 3 15
=
x
3
36
12
Yes, it is equivalent
4
7
16
=
x 10 70
x4
No, it is not
equivalent