Can someone tell me how to explain how to change a percentage to a decimal ???

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

He that is measured at 220° is a reflex angle. the opposite angle is obtuse. find the measure of obtuse .

Over the last 8 nights, elyse earned the following in tips: {105, 120, 84, 95, 100, 132, 140}. if she earns $140 a night for the next four nights, which measure of center would increase more, the mean or median?