According to historical records, Thales, a Greek mathematician and astronomer, used similar triangles's principle to measure the height of the pyramids. His method is to erect a pole in the shadow at the top of the pyramid and form two similar triangles with the help of sunlight. The ratio of tower height to pole height is equal to the ratio of shadow length. From this, the height of the pyramid can be calculated.

Pyramids are distributed in Egypt, America and other places, including upper Egypt and lower Egypt in ancient Egypt, and now Sudan and Egypt. Different sizes, the highest of which is pyramid of khufu, with a height of146.5m and a bottom length of 230m. * * * is made of 2.3 million stones, with an average of 2.5 tons each, covering an area of 52,000 square meters. The pyramids of Egypt are the tombs of ancient Egyptian emperors (pharaohs). One of the eight architectural wonders in the world. They are numerous and widely distributed. The pyramids in Memphis, the ancient city on the west bank of the Nile in the southwest of Cairo, are the most concentrated.

96 pyramids have been discovered in Egypt, the largest of which is located in Giza, a suburb of Cairo.

From about 3500 BC, dozens of small slave countries appeared on both sides of the Nile. Around 3000 BC, an ancient Egyptian country was established. The king of ancient Egypt, also known as Pharaoh, was the largest slave owner in ancient Egypt and had supreme power. They are regarded as the embodiment of God. They built a huge mausoleum pyramid for themselves, which became a symbol of Pharaoh's power. Because these huge tombs are shaped like the word "gold" in Chinese characters, we call them "pyramids". In front of the Harvard pyramid, there is also a sphinx guarding the Pharaoh's tomb.