5:7=х:91

To solve the proportion \( 5:7 = x:91 \), you can use cross-multiplication.

Cross multiplying gives:

\[ 5 \times 91 = 7 \times x \]

Calculating \( 5 \times 91 \):

\[ 5 \times 91 = 455 \]

Now we have:

\[ 455 = 7x \]

To solve for \( x \), divide both sides by 7:

\[ x = \frac{455}{7} \]

Calculating \( \frac{455}{7} \):

\[ x = 65 \]

So, \( x = 65 \).