Final answer:
To calculate the total cost of the dinner, multiply the cost of the meal by the tip percentage and add it to the cost of the meal.
Step-by-step explanation:
To find the total cost of the dinner, we need to calculate the tip amount first. Given that the cost of the meal is $72 and the restaurant added an 18% tip, we can find the tip amount by converting the percent to a decimal (0.18) and multiplying it by the cost of the meal:
Tip amount = 0.18 * $72 = $12.96
Now, we can calculate the total cost of the dinner by adding the cost of the meal and the tip amount:
Total cost of the dinner = $72 + $12.96 = $84.96