Baseball - What is the distance from home plate to second base?

127 feet, 3 3/8 inches (38.8m)

It's not any kind of round number like 90 feet (the distance from base to base). It's 127 feet, 3 3/8 inches from home plate to second base. It's the same exact distance from first to third, too. When constructing a field, the official rules say the first step, after putting home plate down, is to measure from home to second. Then you figure out where first and third should go based on home and second.

https://en.wikipedia.org/wiki/Knickerbocker_Rules