This time of year I often need to see how many acres there are in part of a field, but I don't want to split the field. For example, I run out of fertilizer 150 yards from the edge and want to know how many acres are left. I created a layer and traced that part of the field off my main farming layer but could not define that area to find acres since it wasn't on the main farming layer. How can I find the acres in that outline? Thank you.