Final answer:
To find the total cost of dinner, calculate the tip amount by multiplying the cost of the meal by the tip percentage and then add the cost of the meal to the tip amount.
Step-by-step explanation:
To find the total cost of dinner, we need to calculate the amount of the tip first. The tip is calculated by multiplying the cost of the meal by the tip percentage. In this case, the cost of the meal is $72 and the tip percentage is 18%. So, the tip amount is $72 * 0.18 = $12.96.
To find the total cost of dinner including the tip, we add the cost of the meal to the tip amount. So, the total cost of the dinner is $72 + $12.96 = $84.96.