answersLogoWhite

0

Why is the formula of circle 2pie r?

Updated: 4/28/2022
User Avatar

Wiki User

13y ago

Best Answer

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.

User Avatar

Wiki User

13y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: Why is the formula of circle 2pie r?
Write your answer...
Submit
Still have questions?
magnify glass
imp