pi times the radius squared or pi (approx 3.14) times the diameter
They are all related to circles Circumference = pi * diameter = 2 * pi * radius
for polygons, add up the lengths of all the sides. for circles, multiply the diameter of the circle squared by pi (3.14)
Pi (3.141...) is used for circles, and circles only. You use it to find the area and circumfrence.
In circles in nature.
circumference = 2*pi*radius or pi*diameter
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).
Formulas relating to circles
To calculate properties of circles
Pi is very important for finding circumfrences and area's of circles.
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