Question

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

Answer 1

Answer:

Proportions:

18/8 and 9/4

4/7 and 10/17.5

Everything else is not a proportion

Step-by-step 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.

$\frac{2}{3}$ and $\frac{9}{12}$:

$12\cdot 2= 24\\\\9 \cdot 3 = 27\\\\24 \neq 27$

So these aren't proportionate.

$\frac{3}{8}$ and $\frac{6}{141}$:

$141\cdot 3 = 423\\\\8 \cdot 6 = 48\\\\48 \neq 423$

So these aren't proportionate either.

$\frac{18}{8}$ and $\frac{9}{4}$:

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

So this is proportionate.

$\frac{775}{1}$ (since 775 is just that over 1) and $\frac{27}{20}$:

$775 \cdot 20 = 15500\\\\1 \cdot 27 = 27\\\\27 \neq 15500$

So this isn't proportionate.

$\frac{4}{7}$ and $\frac{10}{17.5}$

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

So this is proportionate.

Hope this helped!