To find the missing number in the equivalent fraction, we can set up the proportion:
\[ \frac{1}{4} = \frac{x}{8} \]
To solve for \(x\), we can cross-multiply:
\[ 1 \cdot 8 = 4 \cdot x \]
This simplifies to:
\[ 8 = 4x \]
Now, divide both sides by 4:
\[ x = \frac{8}{4} = 2 \]
So the missing number is 2.
Thus, the equivalent fraction is \(\frac{1}{4} = \frac{2}{8}\).