Bell WorkFind the unit rate:

$546 lbs

500 miles 10 hours

$42___6 people

$9.00 per pound

50 miles per hour

$7.00 per person

Proportions

A proportion is an equation that states that two ratios are equivalent.

Example:

2 12 3 18

5 159 27

Proportions

=

=

If one of the numbers in a proportion is unknown, mental math can be used to find an equivalent ratio.

Example 1:

2 63 x

x 3

2 63 x Hint: To find the value of x, multiply 3 by 3 also.

2 63 9

x 3

===

If one of the numbers in a proportion is unknown, mental math can be used to find an equivalent ratio.

Example :

28 732 x

28 732 x

Hint: To find the value of x, divide 32 by 4 also.

28 732 8

4

===

4

÷

÷

Circle all of the ratios that are equivalent.

Solve the proportion using equivalent ratios?

4

20

16

20

10

5 30 2 12

In a proportion, the cross products are equal.

=302125

6060

They are a proportion because they equal the same number

Check using cross products!

Use cross products to solve the proportion?

60215 x12015 x8x

602815: Check

120120

Use cross products to solve the proportion?

17951 x15351 x3x

179351: Check

153153

Use cross products to solve the proportion?

125696 x67296 x7x

1256796: Check

672672

You Try: Use cross products to solve the proportion?

64518 x27018 x15x

6451518: Check

270270

You Try: Solve the proportion?

2173 x1473 x49x

217493: Check

147147

Proportion is a statement that says two ratios are equal.◦ In an election, Damon got three votes for each

two votes that Shannon got. Damon got 72 votes. How many votes did Shannon get?

◦ Damon Shannon

n = 48, so Shannon got 48 votes.

n

72

2

3

24

24

2

3

so48

72

Tires cost two for $75. How much will four tires cost?

◦ # of tires cost

n = 150, so four tires cost $150

Proportion

n

4

75

2

2

2

75

2so

150$

4tires

Video:Movie Tickets proportion problem