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π was originally known (to the Greeks, I think) as the ratio of the circumference of a circle to its diameter, thus:
circumference/diameter = π
which with rearranging becomes:
circumference = π x diameter
However, the diameter of the circle is the distance from one point on its circumference to its centre and then onto another point on the circumference so it is also twice the radius in length, that is:
diameter = 2 x radius
which can be substituted back into the formula above to yield:
circumference = π x 2 x radius
or
circumference = 2 x π x radius
which is usually abbreviated, in algebra, to:
circumference = 2πr
with r representing the radius of the circle, and π the ratio as previously described.
What else can I help you with?
Formula of circumference of a circle?
Circumference = 2*pi*radius or pi*diameter
How do you find the distance in inches that a 4inch hour hand on a clock travels in 24 hours?
you need to know the radius or the diameter of the clock remember the circle must be within reach of the hour hand next you workout the formula pie*d or 2pie*r * 24
What is 2pi r?
it is the formula of circumference of circle
What is the formula for finding an area of a circle?
The area of a circle with a known radius can calculated using the following formula where r is the radius : A = Pi(r)2
What is the mathematical formula for the area of a circle?
If a circle has the area A and radius r, thenA = pi * r^2
Formula of circumference of a circle?
Circumference = 2*pi*radius or pi*diameter
What is the formula to find the circumfrenece?
The formula is 2pie(radius).
What is the formula for Bh for circle?
Area formula for circle= --,,- r 2
How do you find the distance in inches that a 4inch hour hand on a clock travels in 24 hours?
you need to know the radius or the diameter of the clock remember the circle must be within reach of the hour hand next you workout the formula pie*d or 2pie*r * 24
Formula to find area of circle?
The area of a circle can be found with the formula (pi)r^2
What is the formula of finding the area of a circle?
Pi * R squared, where R is the radius of the circle in question
What is 2pi r?
it is the formula of circumference of circle
What is the formula for cicumfrance?
The formula for the circumference of a circle is C = 2πr, where C is the circumference and r is the radius of the circle.
What is the area in cm2 of a circle?
The formula for calculating the area of a circle - is Pi x r x r... where r is the radius.
What is the formula for finding an area of a circle?
The area of a circle with a known radius can calculated using the following formula where r is the radius : A = Pi(r)2
What is the mathematical formula for the area of a circle?
If a circle has the area A and radius r, thenA = pi * r^2
Formula for area of circle?
A=pi(r)2 r=radius
