Transcript What does it mean to be proportional?

What does it mean to be
proportional?
When two ratios are equal, they are
PROPORTIONAL
Example: 2 = 6
5
15
5 x 6 = 30
2 x 15 = 30
Look! There cross
Products are equal!!
Try These
6 ? 9
8
12
2 ? 7
3
10
Are these equal proportions?
6 feet
10 sec
?
=
The units are the
same going across
9 feet
15 sec
4 feet
The units are the
same going down
5 feet
10 sec
?
=
4 sec
8 ft
6 ft
?
=
12 sec
18 sec
The units are NOT
the same going
across or down
Try These
5 miles
2 hours
? 15 hour
= 6 miles
$12
32 min
?
$3
8 min
10
15
n
3
What does “n” equal?
Solving Proportions Using
Cross Products
1) Cross Multiply
2) Divide both sides by the value next to
x
3) Solve and label
Practice Problems
8
12
=
6
x
4
x
=
6
15
x
15
=
3
5
On Monday, Jenny makes $125 after working
5 hours. Making the same rate of money,
how much money would Jenny make
working 12 hours?
Susie made punch for a party. She mixed 2
cups of fruit juice with 5 cups of ginger ale.
Using this ratio, how much ginger ale would
she use if she mixed in 5 cups of fruit juice?
Homework Time
Proportions wkst