What is the length of line segment AD?

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

How is the number of vertices for a prism related to the name of the prism

I'm confused on this could anyone me and show me what i need to do to solve it.