Please show steps for both problems thanks!

Which equations represents circles that have a diameter of 12 units and a center that lies on the y-axis? check all that apply

Jose predicted that he would sell 48 umbrellas. he actually sold 72 umbrellas. what are the values of a and b in the table below? round to the nearest tenth if necessary

Identify the type of observational study described. a statistical analyst obtains data about ankle injuries by examining a hospital's records from the past 3 years. cross-sectional retrospective prospective