The area of a circle is 4π ft². What is the circumference, in feet? Express your answer in terms of \piπ.

Danielle has $127.02 in her account before making any transactions. over the course of a week, danielle makes the following transactions: transaction debit ($) credit ($) birthday check 75.00 night out 66.14 garage sale proceeds 121.58 charitable donation 42.25 doctor’s appointment 115.30 at the end of the week, how much money is in danielle’s account? a. $99.91 b. $27.11 c. $184.41 d. $142.16 select the best answer from the choices provided a b c d

Complex numbers multiply √-4 * √-25 and show all intermediate steps. alternative notation is sqrt(-4) * sqrt(-25).

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.