Because all circles are similar.
circumference = 2*pi*radius or pi*diameter
To calculate properties of circles
Pi is a mathematical term relating to circles, and there is no possible way to eat it.
To work out the diameter of a circle with only the circumference, you need to divide the circumference by pi ≈ 3.1416. 1/pi ≈ 0.31831Pi">PiPi is a so far unique number with an endless number of decimals. It is heavily related to math tied to circles and is used in a number of equations involving circles.
Because all circles are similar.
pi times the radius squared or pi (approx 3.14) times the diameter
Pi (3.141...) is used for circles, and circles only. You use it to find the area and circumfrence.
A circle with a diameter of 2 is the guiding cynosure when Pi is the square of all possible circles: If the square root of Pi defines the side of a square and that square can be inscribed within a circle or enclose a circle, then the diameters of all possible circles between the largest and smallest include the circle of which Pi is its perfect square (a diameter of 2).
In circles in nature.
circumference = 2*pi*radius or pi*diameter
WHEN THE TEACHER TELLS YOU THAT YOU NEED TO USE PI...SORRY THAT'S ALL I CAN ANSWER FOR YOU...LATERZWhen you use chords, diameter, and radii in circles
For all circles of all sizes, the length of the circumference divided by the length of the diameter is the same, and this number is the value of pi, which is an irrational number, often it is approximated to 3.14.
Pi is very important for finding circumfrences and area's of circles.
Formulas relating to circles
To calculate properties of circles
Circumference of any circle = 2*pi*radius or pi*diameter