To solve: The proportion −3.512.5=−7n for the given variable n.

Question

Faiza Fuller · Accepted Answer

Approach:
If two ratios are equal then it is a proportion. If

\frac{p}{q}

and

\frac{r}{s}

are two ratios, then

\frac{p}{q} = \frac{r}{s}

is a proportion.
Ex:

\frac{3}{4} = \frac{15}{20}

For finding unknown numbers in proportions, we use cross product to find the unknown number.
Ex:

\frac{2}{7} = \frac{x}{14}

Here in the example x is the unknown number. To calculate the value of x, we use the cross product.
Calculation:
Given

\frac{- 3.5}{12.5} = \frac{- 7}{n}

Apply the cross product in order to find the unknown number.

- 3.5 \times n = 12.5 \times - 7

- 3.5 n = - 87.5

Divide both the sides by -3.5

\frac{- 3.5 n}{- 3.5} = \frac{- 87.5}{- 3.5}

n = 25

The solution for the proportion

\frac{- 3.5}{12.5} = \frac{- 7}{n}

for the indicated variable is

n = 25

To solve: The proportion \frac{-3.5}{12.5}=\frac{-7}{n} for the given variable n.