We know that C = 2 * pi * r. Solve for pi: pi = C/(2R). Thus if (2R) = 1, C will be pi. So draw yourself a circle where the radius is 1/2 and the circumference will be pi.

If the problem is: Given a line segment representing a unit length, how do you construct a line segment with a length of exactly pi, using straight edge and compass? I believe this has been proven IMPOSSIBLE, though there are clever constructions for approximations of pi.

Hi, I'm a fractal artist and mathematician from Tacoma Washington. I'm publishing a paper that will describe EXACTLY where Pi ends. When I say Pi ends, I mean physically ends. If you look at Pi purely from a mathematical view then it will go forever but when you look at Pi geometrically (in other words, when you apply the laws of physics, Pi ends at a very specific point. In this drawing Jason is showing how perfect circles do not exist...anywhere in the universe. Circles are made from triangles as are all shapes and are deeply interconnected with the number Pi. The more trianlges you squeeze within a certain perimeter the closer and closer you approach a circle but you never reach it...you just get closer and closer. This is WHY Pi goes to infininty. Pi is the circumference of a circle (how far around the perimieter) divided by its diameter (the distance from one side of the circle through the center and to the other side). When you add more triangles, the circumference gets slightly larger each time you add more triangles (but by an ever decreasing amount), but the diameter stays the same. A circle with 180 triangles when you divide it's circumference by it diameter you get 3.141433 (Pi accurate to three decimals). A circle with 360 right triangles, one right triangle every one degree, gives you 3.141552 (Pi accurate to four decimals). This picture is 720 right triangles, which when you divide it's circumference by it's diameter gives you 3.141582 (Pi still accurate to four decimals but almost to five). If we could draw a circle with 25,000 right triangles (and nature does this and far more everday) it would be 3.141592645 (Pi accurate to seven digits). What is so amazing about Pi is that everything in the universe breaks down into it. All shapes (icluding circles, and 'perfect circles' don't actually exist..their made from triangles) break down into straight lines and triangles. Every curve breaks down into microscopic straight lines that change angle by very small amounts (just like this picture looks like a curve but is all perfectly straight lines). In math (trigonemetry) they teach how to convert measurements made in degrees (360 degrees is a circle), into measurements made with Pi (this measurement is called Pi radians). To convert degrees into Pi radians you multiply the degrees by Pi/180 (the fraction of pi over 180). All straight lines are 180 degrees (two right triangles make a straight line 90 + 90 =180) and every ttriangle that exists when you add up all three inner angles always equals 180 degrees (the same as the straight line). Since all shapes that exist break down into straight lines and triangles lets see what happens when we convert the degrees into Pi radians. 180 times Pi/180= 180Pi/180 (in words 180 times pi divided by 180). The 180's cancel out because 180 divided by 180 equals one and one times Pi equals Pi! So every shape in the universe breaks down into pieces of Pi, literally. And some say nature doesn't have a sense of humor! This picture is drawn with straight lines only. It is 720 right triangles rotating 1/2 degree at a time. There is no curve but as you can see the more triangles that are sqeezed into the perimeter the more it APPEARS to be a circle or curve. Just like when you look at a mountain and think, that is not a curve or circle, but if you zoom out into outerspace and look at the earth it LOOKS like a perfect sphere. But when you're on the earth it looks completely different. In other words, what is a circle is relative. The mountain is not a circle when you're looking at it one the earth, but it looks like a circle (or part of one) from outspace. This is one of the many beautiful illusions of relativity. For those who like the equation aspect, graph f(x)=xsin(Pi/x) and see what happens. As x (the number of sides to a circle) approaches infinity, f(x) will approach Pi. Last but most important is that we have been taught that Pi never ends. That is true when looking at this in pure equation form...but it is wrong when looking at a 'circle' in reality. This is the really amazing part....Pi ends (physically). The smallest measurement in the universe is something called a Planck length. It was discovered by Maxwell Planck and he won the nobel prize for it. It's accepted and used worldwide by mathematicians, nuclear physicists etc. What this means is that you cannot physically add an infinite number of triangles in a 'circle'. You can keep adding triangles only until each "side" to the circle (microscopic sides) equals one Planck length and this is where Pi physically ends without question. The reason mathematicans have missed this (I think) is because of the lack of viewing math from a purely artistic (pure geometry) point of view. When you do equations of circles you never see with your own eyes like you do when you look at this drawing. We are visual creatures and like they say, a picture is worth a thousand words, or in this case, a thousand million equations. One picture shows visually what most would never find in an equation alone.