8-1 Ratios and Proportions

Learning Target: I will be able to use ratios and proportions to model and solve problems.

Goal 1.02

num, num, num...

This is really just cross-multiplying

ad=bca

b

c

d=

__ __

is equivalent to

Examples: x__y =

5__6

If then 6x= 5y

a c

b d

=

a

b

c

d=

__ __

is equivalent to

Examples:

x__y =

5__6

IfYou're really just flipping the ratios

then y__x =

6

5

__

d

ba

c=

a

b

c

d=

__ __

is equivalent to

Examples: x__y =

5__6

IfYou're taking your numerators and making them a ratio, then take your denominators and make them a ratio.

then x__5

=y

6

__

b

b d

da c ____=

+ +a

b

c

d=

__ __

is equivalent to

Examples:

x__y =

5__6

IfAdd the denominator to the top of each ratio

then x+y

y__ = 5+6

6

___

You can do it!

Try these examples.1.

2.

3.

4.

x

512

7=

__

y+3___8

=y_

45_z =

20_

318___n+6

=6_n

1. x=8.572. y=33. z=.754. n=3