how do you find a diameter if you have a circumfrence of 40
2007-09-23 08:39:27 · 10 answers · asked by jenna m 1 in Science & Mathematics ➔ Mathematics
c=pi*diameter
40=pi*diameter
d=40/pi
2007-09-23 08:46:22 · answer #1 · answered by princess 1 · 0⤊ 0⤋
Well, the circumference of a circle is defined as:
c=2*pi*r, where c is circumference, pi is approximately 3.14...., and r is the radius. the number pi was originally found, because everytime the circumference of a circle was divided by its diameter the answer was always 3.14.... c=2*pi*r can also be written as c=pi*d, where d is the diameter(twice the radius).
so putting in 40=pi*d, d=40/pi, which should equal about 13, just plug 40/(3.14...) in your calculator to find the answer.
2007-09-23 15:50:05 · answer #2 · answered by NBL 6 · 0⤊ 0⤋
You know that the area of a circle is Pi r squared,
& that the circumference is 2 Pi r
is Pi * diameter.
We may rearrange the equation to make the diameter the subject thus the diameter is circumference / Pi,
diameter = 40 / 3.142
diameter = 12.73 [answer].
2007-09-23 16:36:32 · answer #3 · answered by BB 7 · 0⤊ 0⤋
circumference = 2Pi times radius or Pi times diameter
this is because twice the radius is equivalent to diameter
then diameter = circumference /Pi
here Pi = 22/7 = 3.141.....
so your answer should be = 40 x 7/22 = 12.72...
2007-09-23 15:59:29 · answer #4 · answered by Metallurgist 2 · 0⤊ 0⤋
It is pi x the diameter = eg. diameter = 3 & pi = 3.142.
Therefore 3 x 3.142 = 10.260.
The circumference of a 3" diameter ball is 10.26"
Reverse the equasion to find the diameter ie. divide the equasion.
The answer to your question is 12.73.
40 divided by 3.142.
2007-09-23 15:51:55 · answer #5 · answered by Tango 7 · 0⤊ 0⤋
If C=pi*d,
then you can divide both sides by pi and get...
d=C/pi
Plug in your circumference and solve!
2007-09-23 15:46:30 · answer #6 · answered by eaglgenes101 2 · 0⤊ 0⤋
c=pi x diameter
(pi=aprox. 3.14)
40=3.14 x diameter, so
40/3.14=about 12.74
Hope i helped!!!
2007-09-23 15:47:47 · answer #7 · answered by rosierose:) 2 · 0⤊ 0⤋
Divide by pi
(about 3.14)
2007-09-23 15:47:13 · answer #8 · answered by Hi!!! :) 1 · 0⤊ 0⤋
Check this out
2007-09-23 16:00:13 · answer #9 · answered by Ghuijakdan 2 · 0⤊ 0⤋
40/3.14=D
2007-09-23 15:47:55 · answer #10 · answered by taytay5492 1 · 0⤊ 0⤋