Pi's main significance is within its applications!
Pi is obviously used to determine circumference and diameter of circles, if we know what at least one of them is. The other obvious thing pi is used for is anything round. This includes arc lengths. Anything of that sort, pi will have a significant influence on. However, pi has significance in our lives, other than dealing with round objects. Today's world is all about computers. Job applications, tests, homework, work, etc. is constantly being done on a computer. Most people carry a computer around in their pocket. Of course that computer is generally being used for social media, or games, but still it is a computer. When companies want to test the how accurate and efficient a computer is, they actually have it calculate pi to a certain number of digits. In 2002, Professor Yasumasa Kanada calculated pi to 1.24 trillion decimal places (Posamentier & Lehmann) Now one would not assume that every company tests every computer to see how accurate it is. One could guess though that as new technology is introduced, this test is performed. Then depending on how accurate the new technology is, it is then put into further production, making it so pi has the significant impact on computers today.