easy, just divide 2*pi*r by pi*r-squared.
You get 2/r .
First you times 3.14 by the diameter and there you go
The ratio of all lengths is the same. The ratio of the circumferences = ratio of the radii = 2:3
It is the planet's diameter multiplied by pi
d = 9.55 cm
Ratio of circumference is π : 4π = 1 : 4 This is the ratio of all lengths, therefore their radii are in the ratio of 1:4 also. Ratio of areas is the square of the ratio of length → ratio of their areas is 1² : 4² = 1 : 16
To find the ratio of diameter to height, simply divide the diameter of the object by its height. The formula is expressed as: ratio = diameter / height. Ensure both measurements are in the same units for an accurate ratio. This ratio can be used to describe the proportions of cylindrical objects, such as cans or pipes.
Multiply each of the diameters by pi (pi = 3.14159265 or 3.14 for rough approximation) to find the circumferences of the circles.
The diameter of a car tire is 40cm and the diameter of a toy car tire is 18mm. Find the ratio of the diameter of the car to the diameter of the toy car
48 works out as a circumference of 24.5597207 units 75 works out as a circumference of 30.69980124 units So the ratio is about 4:5
If you are given the radius (r) or diameter (d, which is twice the length of the radius) the equation to find the circumference (C) is: C=d(pi) or C=2r(pi).
area = 2pi*r2circumference = 2pi*rThe ratio of their circumferences will be 2pi*r1 /2pi*r2 = r1/r21) r2 = 6pi/2pi = 3. r1 = root(3).2) r = 150pi/2pi = 75. r2 = root(75)So the ratio of their circumferences isr1/r2 = root(3)/root(75)
14 pi inches = a whisker under 44 inches