Ï€ is so pervasive in mathematics that there are many formulae in many different areas of mathematics as well as physics.
Here are some of them:
Area of circle: π*r2 where r is the radius of the circle.
Surface of sphere: 4*Ï€*r2
Volume of sphere: 4/3*Ï€*r3
sin(k*Ï€) = 0 for all integers k.
Here are some less common but intriguing ones:
Leibniz Formula: π/4 = 1 - 1/3 + 1/5 - 1/7 + 1/9 - 1/11 ...
Wallis Product: π/2 = 2/1 * 2/3 * 4/3 * 4/5 *
where the numerators go 2,2,4,4,6,6,8,8, ...
and the denominators go 1,3,3,5,5,7,7,9 ...
and finally, my favourite:
Euler's Identity: eiπ + 1 = 0 which, in 7 symbols, contains the two most important number in basic mathematics: 0 and 1; the two most important transcendental numbers e and π, and the basis of the complex field: i (the imaginary square root of -1).
u0/4
Area of a circle: pi*radius^2 Circumference of a circle: 2*pi*radius or diameter*pi Surface area of a sphere: 4*pi*radius^2
Area of a circle: pi*radius2 Circumference of a circle: 2*pi*radius or diamerer*pi Surface area of a sphere: 4*pi*radius2 Volume of a sphere: 4/3*pi*radius3 Volume of a cylinder: pi*radius2*height
There are thousands of formulae which use pi:Circumference of circle = 2*pi*radiusArea of circle = pi*r^2Area of ellipse = pi*semiaxis1*semiaxis2Surface area of sphere = 4*pi*r^2Volume of sphere = 4/3*pi*r^3pi also appears in some of the most common statistical distributions: the Gaussian (or Normal) as well as Student's t-distribution.
Area of a circle: pi*radius^2 Circumference of a circle: 2*pi*radius or diameter*pi Volume of a sphere: 4/3*pi*radius^3 Surface area of a sphere: 4*pi*radius^2
u0/4
Area of a circle: pi*radius^2 Circumference of a circle: 2*pi*radius or diameter*pi Surface area of a sphere: 4*pi*radius^2
Area of a circle: pi*radius2 Circumference of a circle: 2*pi*radius or diamerer*pi Surface area of a sphere: 4*pi*radius2 Volume of a sphere: 4/3*pi*radius3 Volume of a cylinder: pi*radius2*height
4 * pi = 12.566370614359172953850573533118 But just round it off to 12.57 unless otherwise directed. pi = 3.142... It is a mathematical constant sometimes approximated as 22/7 but if your calculator has a pi function, use it. On my calculator i would type (4) (*) (pi) (=) Pi looks like a squiggly line ~ with two curved lines beneath it, if you are not sure what it is.
There are thousands of formulae which use pi:Circumference of circle = 2*pi*radiusArea of circle = pi*r^2Area of ellipse = pi*semiaxis1*semiaxis2Surface area of sphere = 4*pi*r^2Volume of sphere = 4/3*pi*r^3pi also appears in some of the most common statistical distributions: the Gaussian (or Normal) as well as Student's t-distribution.
V=(4/3)*pi*r^3
Area of a circle: pi*radius^2 Circumference of a circle: 2*pi*radius or diameter*pi Volume of a sphere: 4/3*pi*radius^3 Surface area of a sphere: 4*pi*radius^2
Many properties. For example, 1 + 1/1! + 1/2! + 1/3! + 1/4! + ... = e. This is not true for pi.
Circumference of a circle = 2*pi*radius or pi*diameter Area of a circle = pi*radius2 Volume of a sphere = 4/3*pi*radius3 Surface area of a sphere = 4*pi*radius2 Total surface area of a cylinder = (2*pi*radius2)+(2*pi*radius*height)
Area of a circle = pi*r2 Circumference of a circle = 2*pi*r or pi*d Volume of a sphere = 4/3*pi*r3 Surface area of a sphere = 4*pi*r2 Volume of a cone = 1/3*pi*r2*height Volume of a cylinder = pi*r2*height
9 √(2/pi) We start with the formulas for surface area (4 pi r^2) and volume (4/3 pi r^3). If 4 pi r^2 = 18, then r = 3/√(2 pi); plug that into the formula for volume and we get 9 √(2/pi) as the answer.
If you know the circle's Radius, the area is [ pi times r2 ]. If you know the circle's Diameter, the area is [ 1/4 pi D2 ].