$187.98
1) Since the sale tax is 9%, and the price of the new chair is $172.46 we can calculate the full cost of that chair (price + sales tax) using the following formula:
Notice that 1 represents 100% and 0.09 that 9% into that formula.
Also, we had to round it off to the nearest hundredth since it is a currency ($).
2) Hence, the full cost for that chair and tax is $187.98