Ratios (mathematical)

There are several possible methods for approximate results.

Method I:

Draw a large circle with a known radius. For example, with a peg and string in a field, using chalk to mark out the circle. Measure its circumference carefully. Divide the circumference by the radius.

Method II:

In a unit circle inscribe a square, a regular pentagon, a regular hexagon and so on. Since the radius is 1, the circumference of the circle is, itself, the value of ratio that you want.

You can use trigonometry to calculate its perimeter. Consider a polygon with n sides. Each of its sides forms an equilateral triangle at the centre, and the angle at the centre is 360/n degrees. Therefore, it can be shown that the length of each side is 2*sin(180/n). And then, since there are n sides, the perimeter is n*2*sin(180/n) = 2n*sin(180/n). The circumference of the circle is always outside these polygons so the required ratio is always bigger than this.

Next, repeat with escribed regular polygons - polygons outside the circle. This time it is the tangent ratio that comes into play, and the required ratio is less than 2n*tan(180/n).

With decagons, you get 6.1803 < X < 6.4984

with 20 sided figures you get 6.2574 < X < 6.3354

with 96-gon you get 6.2821 < X < 6.2854 (apparently this is how far Pythagoras got).

Even with 360-sided polygon, - working with sin(1/2) and tan(1.2) - the estimate is accurate to only 3 decimal places.

Method III:

Get a wheel (or a cylinder). Measure its radius. Mark a point on its circumference. Roll it along a smooth surface several times. Measure the distance between the first and the last time the point ouches the surface and divide by 2*(the number of time the point touched the surface - 1). The -1 is because the first time length = 0 and so, in a sense it is the 0th time.

96 males to 100 females.

It is not possible to answer the question because it is not possible t have an are of 54 cm nor a volume of 27 cm. The measurement units are not consistent with the characteristic being measured.

2

If the ratio of similarity is 310, then the ratio of their area is 96100.

The ratio of 11 and 5 is 11:5 or 2.2:1

BMI = Mass : (Height)2 where mass is in kilograms and height is in metres.

Applied to focusing lenses and mirrors, including telescopes, binoculars, and cameras, the focal ratio or 'F-number' is (the focal length of the lens or mirror) divided by (its aperture or diameter)

If you are given one rate, x/y then multiply (or divide) both numbers by any non-zero number. You will have an equivalent rate.

3:4:5

Width:Length = [1+sqrt(5)]/2 to 1 = 1.6180:1 (approx).

It is: 27 to 44 by dividing them by their hcf which is 15

0.75 : 2.20 = 15 : 44

The estimated ratio is 81:919. This excludes people of mixed heritage.

base by height

The ratio is 16 : 10 which may be simplified, if required.

There are four ways to find a ratio.

1 A dealer can normally tell from the vin number.

2 There are normally tags or labels on the axle that have part number, gear ratio, and fluid requirement

info.

3 You can count how many times you have to turn the driveshaft to get one complete turn of the tires.

4 You can divide the number of teeth on the ring gear and divide by number of teeth on the pinion.

Since you have not specified which animal you are talking about, I will decide and select something that is simple: a shark. The ratio is 0.

In the current 112th Congress of the United States of America, there are 242 Republicans in the House and 190 Democrats. There also 3 vacancies. It is fairly close to a 9:11 ratio (real number being 8.63). 55% of the House is Republicans, with just over 45% being Democrats.

I don't know the ratio but I know that men are more likely to become colour blind because women have a backup gene.

Most famous rappers tend to be black. It is impossible to give an exact number, as people's definitions of famous vary. However, there are more famous black rappers than famous rappers of any other race.