that is a lot of answers though
First, you'll use the "Log power rule," which says that

. In this case, you're going from the form on the right (with p in front of the log) to the form on the left (with p in the exponent position). So, the expression becomes:

Then, you'll use the "Log product rule," which says that

. Again, you're going from the form on the right to the form on the left (basically, from the sum of the logs, to a log of the products). So you get:

There's your expression simplified into a simple logarithm.
Answer: 66cm
Step-by-step explanation:
Diameter (d) = 21 cm
c= πd = 22/7 x 21 = 22 x 3 = 66cm