Almost....you missed a "1" in the thousandths place: 3.14159
But, the big thing is to make sure you measure circumference in the correct spot. Generally, that is 4.5 feet off of the ground on the uphill side of the tree. Obviously not every tree is perfect, so there are rules for every situation.
And if you want to get real techincal...circumference is only accurate IF the tree is a perfect circle - which is rare. Calipers are most accurate - measure 2 points at 90 degrees away from each other.
But, the everyday answer to your question is "Yes".