The square root is <span>33.941125497
</span>
You haven't shared the possible answers, so the best I can do (which is very good!) is to assume we want to change from base 4 to base 10 and then apply the change of base formula.
Given log-to-the-base-4-of (x+2), we want log-to-the-base-10 of (x+2). Following the change of base formula,
log-to-the-base-4-of (x+2)
log-to-the-base-10 of (x+2) = ------------------------------------
log-to-the-base-4-of-10
I think the answer would be the 0.039.
Since we are trying to find the number of sequences can be made <em>without repetition</em>, we are going to use a combination.
The formula for combinations is:
is the total number of elements in the set
is the number of those elements you are desiring
Since there are 10 total digits, 
in this scenario. Since we are choosing 6 digits of the 10 for our sequence, 
in this scenario. Thus, we are trying to find 
. This can be found as shown:
There are 210 total combinations.
3.14 (pi) multiplied by 6.9 divided by 4
