The number 90 is spelled ninety. Some people mistakenly spell it ninty, dropping the “e,” but this spelling is incorrect.

An even number, 90 is also a unitary perfect number, semiperfect number, pronic number, harshad number, and Perrin number. The numbers 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45 and 90 are all factors of 90.

**The Number 90 in Sports**

The number 90 is important throughout the world of sports, ranging from field regulations to jersey numbers. In Major League Baseball, each base is 90 feet away from the other, meaning the infield is a perfect square of 90 feet on each side. Professional soccer matches are 90 minutes long and divided into two 45-minute halves. In the NFL, 2002 Defensive Rookie of the Year and seven-time Pro Bowler Julius Peppers is one of the most notable players to ever wear the number 90 on his uniform. In NASCAR, drivers Dick Brooks and Jody Ridley were two of the most famous drivers of the number 90 car.

**The Number 90 in Science**

On the periodic table, thorium (Th) is assigned the number 90. It’s a radioactive metal that was discovered in 1828 and was first used to create a gas mantle.

**The Number 90 in Geometry**

In geometry, a right angle is exactly 90 degrees. A right-angled triangle is when a triangle has one angle that is a right angle or 90 degrees. If all of a triangle’s angles are less than 90 degrees, it’s considered an acute triangle. If one angle of a triangle is larger than 90 degrees, it’s considered an obtuse triangle.

**The Number 90 in Geography **

The latitude for both the North Pole and South Pole is 90 degrees. To call Turkey internationally, one must first dial +90. In the United States, Interstate 90 is the longest interstate highway in the country. It runs across the northern part of the country from Seattle to Boston. It also runs through major cities, like Chicago, Cleveland and Buffalo, and 13 states.

**The Number 90 in Religion **

The number 90 is mentioned at least five times in the Christian Bible. Luke 1:56 mentions that Mary stayed with Elizabeth for three months or 90 days before she gave birth to John the Baptist. In the Jewish Torah, it’s mentioned that Abraham is 90 and 9 years old at the time of his circumcision. Chapter 90 of the Qur’an is called Al-Balad.

**The Number 90 in Health **

The number 90 plays an important role in blood pressure readings. A systolic number (the top number) below 90 is considered low blood pressure, while a diastolic number (the bottom number) above 90 is considered high blood pressure.

**Famous People Who Lived to Age 90 **

British Prime Minister Winston Churchill died at age 90 in 1965. Authors Laura Ingalls Wilder and Upton Sinclair also died at age 90. Other famous people who lived to this age include Herbert Hoover, Florence Nightingale, Colonel Harland Sanders, Clara Barton, Yogi Berra, Chuck Berry, George Martin, Marlene Dietrich, Paul Harvey, Don Rickles, Jack Klugman, and Richard Attenborough.