define pi with the help of circle?

Answer 1

Circumference / diameter

Answer 2

I assume you are trying to derive a value of pi, knowing that pi is defined as the ratio of a circle's circumference/diameter

c=circimferenc
r=radius [or 2r = diameter (d) ]

Two simple methods you can determine pi without using complex mathematics

1) draw a circle of any radius, and using a piece of string measure the circles circumference, then simply determine the value of pi from the definition pi=c/d

note: trying to measure the circumference with a piece of string can be difficult, method 2) may be easier, but take a little more time

2) Draw a circle with any radius (make you circle relatively large to make measurements easier, and make the radius something in inches, rather then partial inches to keep the math simple)

now draw a line for the diameter going through the the center point of the circle, and another at right angles to the first line again going through the center point

without the circle you should have something looking like this

__|__ a
....|
....b

(the periods are only there to fill the space with this font)

Now measure the distance between points a and b (a, b are points where the line intersects with the circle)

If you radius was 1 unit, then the measurement will come out to about 1.41 units

Take this value and multiply it by 4, this will approximate the circumference of the circle. Note we are using the perimeter of the square to approximate the circumference.

plug in 5.64 (4x 1.41) for formula for pi, 5.64/2 = 2.82

But you know pi = 3.14?

The error is because our approximation, it is too genereous.

As you keep dividing the circle into more equal triangles, and measuiring the side of the triangle towards the radius, the value will become closer and closer to the real value of pi.

I'll leave it for you to try the rest

Answer 3

In Euclidean plane geometry, Pi is defined either as the ratio of a circle's circumference to its diameter, or as the ratio of a circle's area to the area of a square whose side is the radius.

When a circle's diameter is 1, its circumference is Pi.

Answer 4

By definition, pi is the ratio of the circumference of a circle to its diameter. Pi is always the same number, no matter which circle you use to compute it.
For the sake of usefulness people often need to approximate pi. For many purposes you can use 3.14159

Answer 5

Pi is half the distance around a circle with a radius of 1.

Answer 6

Circumference of a circle divided by its diameter. Always the same set ratio of approx 3.1415927 (or 22/7) and represented by the Greek letter for P.

Answer 7

In mathematics a number that is approximately equal to 3.14159 that is the ratio of the circumference of a circle divided by its diameter and is represented by the symbol π

Answer 8

One radian is defined to be the angle subtended by the arc of a circle of length equal to the radius of the circle.

A full circular arc will subtend an angle of 2 п radian.

П is an irrational number.

The approximate rational number is 22/7.

Answer 9

pi is the relationship between the diameter or radius of a circle to its circumference.. or in equation..Circumference = Diameter x pi = 2 x pi x radius..oki..

Answer 10

the ratio of the circumference to the diameter of a circle; approximately equal to 3.14159265358979323846...