90: A Pivotal Numerical Milestone

90: A Pivotal Numerical Milestone

90 is a significant number with numerous historical, cultural, and mathematical implications. Here are some key aspects associated with 90:

Historical and Cultural Significance:

In many cultures, 90 represents completion or a full circle.
In Chinese astrology, 90 is considered a favorable number associated with blessings and longevity.
In Islam, the number 90 is mentioned in the Quran as the number of days for new mothers to observe a postnatal period of purity.

Mathematical Properties:

90 is a composite number, divisible by 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, and 90.
It is a highly composite number, having 12 divisors.
90 is the sum of three consecutive prime numbers: 23 + 29 + 37.

Physical Properties:

In astronomy, 90 degrees is a right angle, which plays a crucial role in geometry and trigonometry.
The boiling point of water at sea level is approximately 90 degrees Celsius or 212 degrees Fahrenheit.

Other Notable Facts:

In the United States, the speed limit on many highways is 90 mph.
The first ZIP code in the United States was 90001, assigned to Beverly Hills, California.
90 is the atomic number of thorium, a radioactive element used in nuclear power plants.

90 is a versatile number with a rich history and significance across various fields. It represents completion, blessings, and unique mathematical properties, making it a fascinating number to explore.