π（Pi） Day falls on March 14. This is the day when mathematicians and geometry（几何学）lovers around the world get together and celebrate the mathematical constant（常数） of Pi.
Firstly, the date which can be represented numerically in the format 3. 14represents the first 3 digits of π. Besides, one of our greatest physicists Albert Einstein was born on March 14,1897. In 2018, the famous physicist Stephen Hawking passed away on Pi Day.
The earliest known celebration of Pi Day was organized by the physicist Larry Shaw at the San Francisco Exploratorium in 1988, featuring eating different kinds of fruit pies. The museum staff marched around a circular room, sang songs, and ate pie. News stories about the celebration spread the idea to schools, museums, and communities. In 2009, US House of Representatives officially named this special day—"Pi Day".
Many people celebrate Pi Day with family and friends. People make pizzas （round ones, of course） and bake cream pies. Some people even use a special pie pan shaped like the Greek letter π. They are also willing to drink pi-neapple juice.
Over thousands of years, people tried to unfold the puzzle behind this magic number. Before the appearance of modern computing technologies, mathematicians all over the world have made their efforts on calculating the approximation of Pi. While Indian mathematician
Aryabhata approximated Pi to using the circumference of a polygon（多边形） with 384 sides. On 2019's Pi Day, Google announced that the calculation of Pi has already reached 31. 4 trillion decimal（小数的） places.
A. The most popular way is by eating pi-themed foods.
B. March 14 seems to be tightly connected with Science.
C. It was because "Pi" and "pie" sounded same in English.
D. The world record for memorizing pi is held by Chao Lu from China.
E. Chinese ancient mathematician Zu Chongzhi extended Pi to 7 decimal places.
F. Another celebration is to recite this amazing number with countless decimal places.
G. Pic an also be used to calculate the volume of something shaped like a ball or a tube.
