Suppose that ABCD is a parallelogram. Draw line EF from the midpoints of AD and BC. Are lines EF and AB congruent? Will give brainliest!

An air conditioning system can circulate 350 cubic feet of air per minute. how many cubic yards of air can it circulate per minute?

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.

Can someone tell me if this is perpendicular? !