Answer
4 is 5% of 80.
Work Step by Step
$\frac{part}{whole}=\frac{percent}{100}$
$\frac{4}{80}=\frac{x}{100}\longrightarrow$ Cross multiply then solve for x
$80x=(4)(100)\longrightarrow$ Simplify
$80x=400\longrightarrow$ Divide both sides by 80
$80x\div80=400\div80\longrightarrow$ Simplify
$x=5$
