Find $f(3)$. Which piece of the function should be used to find $f(3)$ ? \[ f(x)=\left\{\begin{array}{ll} x+2 & \text { if } x<1 \\ x-1 & \text { if } x \geq 1 \end{array}\right. \] $x+2$ $x-1$

Step 1 ：The function is defined as \(f(x)=\left\{\begin{array}{ll} x+2 & \text { if } x<1 \\ x-1 & \text { if } x \geq 1 \end{array}\right.\)

Step 2 ：We need to find \(f(3)\).

Step 3 ：Since 3 is greater than 1, we should use the second piece of the function, \(x-1\), to find \(f(3)\).

Step 4 ：Substitute \(x = 3\) into \(x - 1\) to get \(f(3) = 2\).

Step 5 ：Final Answer: \(f(3) = \boxed{2}\)