I think 517.26
I did 10 times 3^2 (9) it equals 90. Then 90 times 3.14 and got 282.74. Then did 800- 282.74 and got 517.26
Okay, so this is exponential. The formula for the exponental function is Y=ab^x
a is the y-intercept
b is the rate/ratio
x is the time
According to the graph, (remember the y-intercept is in the y-axis) so 2 is the y-intercept.
Knowing what the y-intercept is, you know what the answer is.
A.