How do you do the Pythagorean Theorem? Also how do you do it with one leg and hypotenuse? Also how do you do it with 2 legs and no hypotenuse?

The human resources manager at a company records the length, in hours, of one shift at work, x. he creates the probability distribution below. what is the probability that a worker chosen at random works at least 8 hours? 0.62 0.78 0.84 0.96