Well i know its the Circumferance of a circle but i dont get it! Ive got a mathematics exam on the 10th and i need help on how to understand it. My teacher said that you should remember it by.. I like eating pie whilst listening to a CD. But im like ermm i dont understand but he explains to me but i am brainwashed about it. Please help!
2007-05-06 03:25:54 · 9 answers · asked by Jadee 1 in Science & Mathematics ➔ Mathematics
The usual form for equations relating to a circle is:
C = 2pi*r
C = pi*d
A = pi*r^2
A = pi*d^2 / 4
where
C is the circumference;
r is the radius;
d is the diameter; and
A is the area.
The formula you quote either uses confusing notation, or is incorrect.
2007-05-06 03:37:18 · answer #1 · answered by Anonymous · 0⤊ 0⤋
If you are confused try thinking about it this way. The Greeks who were big on geometry studied many shapes and found that for every circle you draw if you divide the circumference by the diameter the answer is always the same. namely 3.14159265359............. this has been named pi and it is an irrational number that is to say people have yet to calculate an answerer which either has no remainder or where the digits start to repeat. What pi is is the ratio of the circumference and the diameter. It can also be written as 22/7. Its use is that it allows you to find the circumference of a circle if you know the diameter (most useful as it is very hard to measure accurately) or the diameter if you know the circumference. You do need to learn the formula correctly though if you want to use them
2007-05-07 03:56:39 · answer #2 · answered by Jeniy 2 · 0⤊ 0⤋
The cicumference is the distance around the edge of a circle
Pie is just a number (3.14...) that helps you work out stuff to do with circles.
D is diameter which is the width of the circle.
So circumference + pie * Diameter.
If you still don't understand it I wouldn't worry about it too much as long as you remember it and know how to use it.
2007-05-06 03:34:00 · answer #3 · answered by AnythingCanHappen! 5 · 0⤊ 0⤋
circumference is distance around entire circle - or perimeter if it's easier to think of it like that.
diameter is the longest width of the circle ( also found as 2 times the radius)
so the equation just shows you how the two relate which is by the constant pi.
might be cool to know that pi is actually defined as ratio of circumference to diameter (c/d)
isnt anything to it really
2007-05-06 03:34:43 · answer #4 · answered by Rich W 2 · 0⤊ 0⤋
circumference of the circle means it is the length of the string placed on the circle when measured ...for this measure their is a formula c = pie D where the value of pie is 22/7 or 3.14 and D is the diameter or twice the radius of the circle
2007-05-08 20:39:43 · answer #5 · answered by billako 6 · 0⤊ 0⤋
Hate to burst your bubble but circumference = pi x diameter or 2 x pi x radius. pi x r squared is the area of a circle.
2007-05-06 03:30:55 · answer #6 · answered by Del Piero 10 7 · 1⤊ 0⤋
I'm not surprised you don't get it, the formula is all mixed up.
....................................................................................................
If D is the diameter then D = 2 x r where r is the radius so
C = Pi x D^2 = Pi x (2r)^2 = 4 x Pi x r^2
This is the formula for the curved surface area of a sphere
........................................................................................................
If C is the circumference of the circle then the formula is C = Pi x D where D is the diameter of the circle and the squared bit is wrong.
2007-05-06 07:14:05 · answer #7 · answered by fred 5 · 0⤊ 0⤋
If D is the RADIUS of the circunsference pi*D^2 is the Area
2007-05-06 03:31:10 · answer #8 · answered by santmann2002 7 · 1⤊ 1⤋
you have just mixed up your equations. if you allowed e-mail i could send you a simple diagram to remember. Where do you live anyway?
2007-05-09 03:52:16 · answer #9 · answered by landales 1 · 0⤊ 0⤋