Answer
The value of the function is $f\left( 3 \right)=0.93\text{ dollars}$.
Work Step by Step
Consider the graph. The cost of mailing a letter of weight 3 ounces is the value of the function at a weight of 3 ounces.
It can be observed from the graph that the cost or $f\left( x \right)$ remains the same for the interval from 2 to 3 ($\$0.93$).
