To find the missing value in the equivalent fraction \( \frac{5}{?} = \frac{20}{28} \), we can cross-multiply:
\[ 5 \cdot 28 = ? \cdot 20 \]
Calculating \( 5 \cdot 28 \):
\[ 5 \cdot 28 = 140 \]
Now, our equation is:
\[ 140 = ? \cdot 20 \]
To find the missing value, divide both sides by 20:
\[ ? = \frac{140}{20} \]
Calculating \( \frac{140}{20} \):
\[ ? = 7 \]
Thus, the missing value is \( 7 \).
So, the answer is \( 7 \).