4. \( 2 l+2 w \) when \( l=5.7 \) and \( w=2.3 \)

To solve for the perimeter \( P \) using the formula \( P = 2l + 2w \), simply substitute the given values of \( l \) and \( w \) into the equation. First, \( P = 2(5.7) + 2(2.3) \). This simplifies to \( P = 11.4 + 4.6 \), which equals \( 16 \). So, the perimeter is \( 16 \) units. To visualize this, think of a rectangular garden where the length is 5.7 meters and the width is 2.3 meters. With a perimeter of 16 meters, you can easily plan how much fencing you'll need to enclose that space!