I figured out how to do this.  Here is the instructions incase someone else has this problem.

Digits:=n     #will the number or precise digits to n

evalf(sqrt(x))  #will evaluate the floating point answer of sqrt(x) to a precision of n floating point digits.

This problem probably belongs in the Math Help Forum, as you have not posted a question about using maple.  In any case I don't think you have provided enough information for someone to help you with your problem. 

I am not sure what you mean by the area beneath f(x) and g(x), did you perhaps mean the area between the two functions or the area that is beneath both functions?

Also I am not sure it makes sence to talk about the area at a point C, did you mean that the area from point a to point c?

Laura