Final answer:
The sales tax on a $779 smartphone purchase in Arizona, with a 5.6% sales tax rate, is $43.62 when rounded to two decimal places.
Step-by-step explanation:
Peter bought a smartphone in Arizona for $779, and the sales tax rate in Arizona is 5.6%. To find the sales tax of the retail purchase, we need to convert the percent into a decimal and multiply it by the total cost.
Convert 5.6% to a decimal: 5.6% = 0.056.
Multiply the decimal by the cost of the smartphone: $779 × 0.056.
This gives us the amount of sales tax, which when calculated is: $43.624.
After rounding to two decimal places, the sales tax is $43.62.