#### Explanation:

The formula for calculating the Total Cost is:

$T = c + s \cdot c$ Where $T$ is the total cost, $c$ is the cost of the product and $s$ is the sales tax percent. For this problem we are give the cost of the product (c = $80) and the sales tax percent (s = 6%). We can substitute these into the formula and solve for $T$: T =$80 + (6% * $80) "Percent" or "%" means "out of 100" or "per 100", Therefore 6% can be written as $\frac{6}{100}$which gives us the equation: T =$80 + ((6/100)*$80) Solving this gives: T =$80 + (($480)/100) T =$80 + $4.80 T =$84.80