How do you get the circumference of a circle with the diameter?

Me answer number 3plz explain how you do it

One of every 20 customers reports poor customer service on your company’s customer satisfaction survey. you have just created a new process that should cut the number of poor customer service complaints in half. what percentage of customers would you expect to report poor service after this process is implemented? 1.) 5% 2.) 10% 3.) 2% 4.) 2.5%

Question 10 of 211 pointuse the elimination method to solve the system of equations. choose thecorrect ordered pair.10x +2y = 643x - 4y = -36a. (4,12)b. (-3, 11)c. (2,10)d. (-5, 8)