The circumference of a circle is about 53.38 cm. The radius of the circle is 8.5 cm. Which expression best represents the value of pi? Will give brainliest!!

Acredit card advertises an annual interest rate of 23%. what is the equivalent monthly interest rate?

We just started the introduction into circles and i have no idea how to do this.

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.