The exchange rates listed in the box on the left are best described as typical. Nothing official but what they seem to be. It’s a reasonable guide. But, there is an official rate — different for buying and selling — which is easy to find.
All the banks will have that information. You will find it posted in the banks but you can also find it on-line. For example, Banrural has the exchange rates for both US dollars and Euros listed on their web site.