I need to find DF of this circle segment.

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?

Monitors manufactured by tsi electronics have life spans that have a normal distribution with a standard deviation of 1800 hours and a mean life span of 20,000 hours. if a monitor is selected at random, find the probability that the life span of the monitor will be more than 17,659 hours. round your answer to four decimal places.