We can find the diameter of the circle by replacing some values in the formula for circumference. The formula for find the circumference is pi * d, where pi could equal 3.14 or 22/7 and d is the diameter. After dividing pi from both sides (I used 3.14), we have the total of about 21.01, which would be our diameter. We add 4 more feet into it, resulting in 25.01 feet, and we just multiply that by $0.45 to get the total price.
We get around $11.25 as our total price.