Raytheon Co., the Waltham-based defense contractor that is big advocate of so-called STEM education, marked Pi Day earlier this week by delivering hundreds of apple pies to math and science teachers at middle and high schools located within a 3.14-mile radius of several Raytheon facilities across the country.

The purpose of this exercise was to highlight the importance of pi calculations in science, technology, engineering, and math --- the so-called STEM subjects – and to thank teachers for encouraging their students to get inspired by STEM. Pi, as most arithmetic whizzes know, is the mathematical constant roughly equal to 3.14, and in certain circles, it is celebrated on March 14 --- a.k.a. 3/14.