Question

HELP ASAP!! Use cross products to determine which are valid proportions.

Proportion
Not a Proportion
2/3 and 9/12
3/8 and 6/141
18/8 and 9/4
775 and 27/20
4/7 and 10/17.5

Answer 1

Proportions:

18/8 and 9/4

4/7 and 10/17.5

Everything else is Not a Proportion

Correct on edge as well ;P

Explanation:

Answer 2

Proportions:

18/8 and 9/4

4/7 and 10/17.5

Everything else is not a proportion

Explanation:

To find if two fractions are a proportion, we need to set each up as a fraction. Then, we multiply both diagonal values. If we get the same value, they are proportionate.

`(2)/(3)` and
`(9)/(12)`:

`12\cdot 2= 24\\\\9 \cdot 3 = 27\\\\24 \\eq 27`

So these aren't proportionate.

`(3)/(8)` and
`(6)/(141)`:

`141\cdot 3 = 423\\\\8 \cdot 6 = 48\\\\48 \\eq 423`

So these aren't proportionate either.

`(18)/(8)` and
`(9)/(4)`:

`18 \cdot 4 = 72\\\\9 \cdot 8 = 72\\\\72 = 72`

So this is proportionate.

`(775)/(1)` (since 775 is just that over 1) and
`(27)/(20)`:

`775 \cdot 20 = 15500\\\\1 \cdot 27 = 27\\\\27 \\eq 15500`

So this isn't proportionate.

`(4)/(7)` and
`(10)/(17.5)`

`4\cdot 17.5 = 70\\\\7 \cdot 10 = 70\\\\70 = 70`

So this is proportionate.

Hope this helped!