Final answer:
Giovanni's pastry costs $4.50 before tax. After adding a 10% sales tax, which is $0.45, the total price he pays is $4.95.
Step-by-step explanation:
To calculate the total price Giovanni pays for the pastry including a 10% sales tax, you first need to determine the amount of sales tax by converting the percentage to a decimal. You do this by dividing the tax rate by 100. In this case, 10% becomes 0.10. Next, you multiply the price before tax by the decimal sales tax rate.
The price of the pastry before tax is $4.50. Therefore, the sales tax is calculated as follows:
$4.50 × 0.10 = $0.45.
After finding the amount of sales tax, you add it to the original price to find the total price Giovanni will pay, which is:
$4.50 + $0.45 = $4.95.