The ratio of circumference to height of pyramid of khufu, which was built around 2500 BC, is twice that of pi. Of course, this may be just a coincidence, because we know that the ratio of the circumference to the diameter of a circle is 2 times π, and the bottom of the pyramid is square, which means that the ancient Egyptians have solved the geometric problem of turning a circle into a square.
Although this may be a coincidence, the Egyptians took the lead in calculating pi. The mathematical papyrus of Reinde, an ancient Egyptian cultural relic, records that pi is equal to the square of score 16/9, which is about 3. 1605. At the same time, a Babylonian stone tablet also records that pi is equal to 25/8, which is 1000 years later than ancient Indian Brahms.
Brief introduction of pi
Pi refers to the ratio of circumference to diameter of a circle, that is, pi = circumference ÷ diameter, which is generally expressed by the Greek letter π and is a common mathematical constant in mathematics and physics. π is also equal to the ratio of the square of the area and radius of a circle, that is, π = the area of a circle ÷ radius 2 is the key value to accurately calculate the geometric shapes such as the circumference of a circle, the area of a circle, the volume of a sphere, etc. In the analysis, π can be strictly defined as the smallest positive number x satisfying sinx=0.
Pi is represented by the Greek letter π, which is a constant (approximately equal to 3. 14 1592654) and represents the ratio of circumference to diameter. It is an irrational number, that is, an infinite cycle decimal. In daily life, pi is usually expressed as 3. 14, which is used for approximate calculation. 3. The nine decimal places of141592654 are enough for general calculation. Even if engineers or physicists want to make more accurate calculations, they only need to take the values to a few hundred decimal places at best.
The above contents refer to Baidu Encyclopedia -Pi.