If a sample of 25 students is taken from a population of 179 students, the population variance, o^2, is the variance of how many students' heights?

Triangle knm is what is true about the sides of knm

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min

Ithink i know it but i want to be sure so can you me out ?