Convert the percent into a decimal by multiplying by 0.01: the percent in this problem is 6.5%, so when you multiply by 0.01, you get 0.065
Multiply the price by your new decimal: in this case, that would mean to multiply 1580 by 0.065, which gives you 102.7. Keep in mind that this is just the tax, not your final answer.
Add the tax you just calculated to the original price: add 102.7 to 1580 to get 1,682.7. That is your final answer.