## Algebra: A Combined Approach (4th Edition)

From the change of base formula, we know that $log_{b}a=\frac{log_{c}a}{log_{c}b}$ ($a$, $b$, and $c$ are positive real numbers and neither $b$ nor $c$ is equal to 1). Therefore, $log_{4}9=\frac{log_{10}9}{log_{10}4}=\frac{0.9542}{0.6021}=1.5850$.