My first wife was an editor for a large textbook publisher, back in the 1960's. She told me then that Texas used the pi = 3 value in all math books until high school, when they had to fess up to make algebra and geometry work right. When I was in elementry school, we used "about 24/7" which worked out well enough when we were learning fractions. Now that we have calculators, of course, no one learns fractions any more.
However, if you use an appropriate non-Euclidian geometry, 3.0...
might be just right. Try calculating the area of circles drawn on the surface of a sphere!
She also said that Texas had a committee of fundamentalists who passed judgement on all textbooks, and her company therefore had to publish a different set of books for Texas.

MD