To solve for the unknown variable \( b \) in the formula \( A = bh \), we can substitute the given values into the equation.
Given:
- \( A = 50 \)
- \( h = 10 \)
Substituting these values into the formula:
\[ 50 = b \times 10 \]
To solve for \( b \), divide both sides of the equation by 10:
\[ b = \frac{50}{10} \] \[ b = 5 \]
So, the value of \( b \) is \( 5 \).