Can someone help me I really don’t understand this..

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

Apool measures 12.3 feet by 16.6 feet. if the longer wall of the pool has a diagonal of 17.8 feet, what is the volume of the pool? (round to nearest tenth)

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?