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Question

Find the missing number in this proportion.

30
Division Line = Division Line
90 18

Answer 1

To find the missing number in the proportion \( \frac{30}{90} = \frac{x}{18} \), we can cross-multiply:

\[ 30 \cdot 18 = 90 \cdot x \]

Calculating the left side:

\[ 30 \cdot 18 = 540 \]

So, the equation becomes:

\[ 540 = 90 \cdot x \]

Now, we divide both sides by 90 to solve for \( x \):

\[ x = \frac{540}{90} \]

Simplifying the fraction:

\[ x = 6 \]

Therefore, the missing number is \( 6 \).