Hello there. To solve this question, we'll have to remember some properties about changing bases in logarithms.
Given the logarithm:
We first use the properties:
Now, we use the change of basis formula:
When changing for a basis d greater than zero and not equal to 1.
With this, we have that
Applying the property:
and knowing that 4 = 2², we get
We chose base 10 log because we know the following values for:
Hence the approximation for what we want is
This is the answer we're looking for.