Because "pi" is the Greek letter for "P" and is used to represent the ratio of a circles diameter to it's circumference. "Pie" just happens to conveniently be the pronunciation of that Greek letters name and a very tasty desert.
The ancient Greek mathematician Pythagoras is usually creditted for the discovery of the ratio of circumference to radius of circles. That is, Circumference = 2 * Pi * Radius. The number Pi represents (3.1415....) is named after him.
It is: circumference/diameter = pi
Pi is the ratio of the circumference ( the perimeter) of a circle to its diameter. You might have learned in school that if C is the circumference of the circle., then C=2Pir or C=pixd from which we say pi = C/d or the ratio of the circumference of the circle to its diameter. This has been known since ancient times! William Jones gave us the symbol we currently use for it. This comes from the 16th letter in the Greek alphabet. So we use it to measure circles because of what it is.
it is a number like 9958
It is the 16th letter of the Greek alphabet. In mathematics it is the ratio of the circumference of a circle to its diameter
pi is a letter in the greek alphabet (π) which in math represents the irrational number value of 3.141592653589793238462... we use pi as a variable instead of writing out the endless decimal everytime it is used. By this, we can calculate the area and circumference of circles, you can find the area by πr2 which r is the radius or radii, and to find the circumference it is 2πr.
Pi which is not really a "word" but the Greek letter: π
The ratio of circumference to the diameter of a circle is 3.14159 ... This value is called "Pi" and is represented by the Greek letter π.
The word "Pi" derives from the letter "P" (π) out of the Greek alphabet, which's the first letter of the word "περιφέρεια" - peripheria meaning periphery, respectively "περίμετρος" - perimetros, Greek for circumference.
pi is represented by the Greek letter (of the same name) π and is the ratio of the circumference of a circle to its diameter.
In geek letters, "Alpha" often refers to the first letter of the Greek alphabet. It is commonly used in technology and gaming contexts to signify the early or initial stages of a project or software release. 'Alpha' can signify that a product or software is still in a testing phase and may not be fully functional or stable yet.