Solve Proportional Relationships - mathcounts4ever.com

NAME DATE PERIOD Lesson 6 Reteach Solve Proportional Relationships A proportion is an equation that states that two ratios are equivalent. To determin...

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PERIOD

DATE

NAME

Lesson 6 Reteach Solve

Proportional Relationships

A proportion i s a n e q u a t i o n t h a t s t a t e s t h a t t w o r a t i o s a r e e q u i v a l e n t . T o d e t e r m i n e w h e t h e r a p a i r o f ratios f o r m s a proportion, u s e cross products. You c a n also u s e cross products t o solve proportions.

Example 1 Determine w h e t h e r the p a i r of ratios — a n d — form a proportion. 24 18 F i n d t h e cross products. 24 . 1 2 = 288 20 . 1 8 = 360 Since t h e cross p r o d u c t s a r e n o t equal, t h e ratios d o n o t f o r m a proportion.

Example 2 k

12

70'

k 12 30 70 • 7 0 -30 .

Write the equation. Fmd the cross products.

8 4 0 = SOk 840 30k 30 30

Multiply. Divide each side by 3 0 .

28 = k

Simplify.

T h e solution is 28.

Exercises Determine w h e t h e r e a c h p a i r of ratios forms a proportion. 1.

I I 12 10' 5

/\I0

2.1

4.

7 13 15' 32

Aid

5

4 12

1^0

8. 2 0 3 0 35' 45

2

7

r 71

a

12 9' 18

3. _ 8 _ 1 0 12' 15

1

6.

' 9 ' 63

8 12 24' 28

9. 1 8

24' 4

E

3 if

Solve e a c h proportion.

i

! I e

I I

12.

^ 1

.3.

16.

24

=

f =

14.48 = VL.

15 2.8 7

-J

/J /7

7

17. ^" y 1 6 . 8

Course 2 • Chapter l R a t i o s a n d P r o p o r t i o n a l R e a s o n i n g

1 = 1r 0

15^ 1 4 ^ 1 0 -^2

-t

a: 18

)0 36

/o

NAME

V

DATE

PERIOD

Lesson 6 Extra Practice Solve

Proportional Relationships

Solve each proportion. 3

4

^ ^

w

^- p y t - z -

5=15 t 0.3

^•5

/

3

- i t

„ 36 a 8.

I

6-4

0^

SI 3 6 3-

3

- 4

4

12

W>7

8^=7

^= -^ Sr 5 ^ I

3

«

2.5

6?

SA-

i 20

•1

-8- 1 2

u

Course 2 • Chapter 1 R a t i o s a n d P r o p o r t i o n a l R e a s o n i n g

21

^ =^