A hot air balloon is descending at a rate of 6.75 feet per second. What is the change in the balloons height after 3 1/2 seconds?

Point $(x, y)$ is randomly picked from the rectangular region with vertices at $(0,,,2010),$ and $(0,2010)$. what is the probability that $x > 7y$? express your answer as a common fraction.

Find the value of the cosine for angle a

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.