The equation of a circle is x2 +y2 =81 what is the diameter of the circle

Shiny white dental insurance costs $258 per year. approximately one-third of insured people need a filling, which averages $110 each. 80% of insured people get a preventive check-up each year, and the average cost of this visit is $95. if you consider shiny white’s income and expenses, what is the expected value of each insured customer?

What is the value of x? enter your answer in the box. photo attached.

A(t)=728(1+0.04)^t how much money did aditya originally invest