First, I am not an expert in strawberry production, so take that into account....

The logic is that the effective growing width for your strawberries is 36" (3 ft).  I can see that... and agree with that logic ...

So,  3' / 7.5' x 1.75 acres = 0.7 acres actual production.

500 ft long x 3' ft wide x 19 rows = 28,500 sq ft / 43,560 sq ft per acre = 0.65 acres of actual berry producing area.  

So, yes, use either 0.65 acres or 0.7 acres production area, which ever way you want to calculate.

Penn State has a Commercial Vegetable Production Guide.  I was thinking you needed to buy it. However, you can download portions of it as pdf for free.  So, maybe you want to download the sections that would fit your operation.  Maybe it will be helpful, maybe it won't. It won't cost you anything but your time.  Just a thought.

edit: I wanted to add.... looking at some of the recommendations for fertilizing berries, they are based on nutrients per 1000 sq ft.  This is for homeowners.  So, to me, this would support the idea of using 0.65 or 0.7 acre as your actual production area, not the 1.75 acres.   

Another way to look at it..... if you plant your beds on 5' centers..... or 7.5' centers.... or 10'ft centers.... your actual producing width is still 3'.  Again, another argument to say your production area is 0.65 or 0.7 acres, not 1.75 acres.