in the figure shown, which pair of angles must be complementary?
∠aoc and ∠dob
∠cod and ∠dob
∠cob and ∠aoc
∠aoc and ∠cod

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.

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !

Me i’m stuck on all these questions besides the two bottom ones