To determine if Keith's guess of 8 is correct for the equation \( ? \div 2 = 4 \), we can solve the equation.
To find the value of \( ? \), we can multiply both sides of the equation by 2:
\[ ? = 4 \times 2 \]
Calculating the right side gives:
\[ ? = 8 \]
Since \( ? \) equals 8, Keith's guess of 8 is indeed correct.