P.I.

Classical computers have managed the calculation for molecules as large as pentacene, a chain of five hydrocarbon rings with 22 electrons in “pi” covalent bonds, which govern the molecule’s shape and reactivity.

Most numbers don’t have names, but pi does.

Today, using sophisticated computers, researchers have come up with trillions of digits for pi, but there is no end.

The nerdy holiday, observed on March 14 because the first three digits of pi are 3, 1 and 4, has been recognized by the U.S.

For example, pi times the radius squared, find the area of a circle to calculate pressures on hydraulic cylinders.