# ratio

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## ratio.

The ratio of two quantities expressed in terms of the same unit is the fraction that has the first quantity as numerator and the second as denominator. For example, if in a group of 100 people 5 die, the ratio of deaths to the total number in the group is 5/100=1/20=.05. Ratios are indicated also by writing the two values with a colon between them, e.g., the ratio of 4 to 8 can be expressed by 4:8 as well as by 4/8.

## Ratio

A relationship in magnitude, quantity, or degree between two or more similar things.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Ratio

The ratio of two numbers is the quotient from the division of the first number, by the second. The ratio of two homogeneous magnitudes is the number obtained by measuring the first magnitude when the second is chosen as the unit of measurement. If two magnitudes are measured in the same unit of measurement, their ratio is equal to that of the numbers that measure them.

The ratio of the lengths of two segments may be expressed by a rational or irrational number. In the former case the segments are said to be commensurable, and in the latter incommensurable. Mathematicians of the ancient world had no knowledge of irrational numbers. For them the concept of the ratio of two segments did not reduce to the concept of number. In their conception the geometrical theory of the ratios of magnitudes was not connected with the concept of number and played an independent role. In a sense, it substituted for a theory of real numbers. Indeed, according to Euclid the four segments, a, b, a’, and b’ form the proportion a: b = a’:b’ if for any natural numbers m and n one of the relations ma = nb, ma > nb, ma < nb is satisfied simultaneously with the corresponding relation ma’ = nb’, ma’> nb’, or ma’ < nb’. It follows that when a and b are incommensurable the subdivision of the rational numbers (x = m/n) into two classes according to whether a > xb or a < xb coincides with the subdivision according to whether a’ > xb’ or a’ < xb’ —this is the idea behind the modern theory of Dedekind cuts.

## ratio

[′rā·shō]
(mathematics)
A ratio of two quantities or mathematical objects A and B is their quotient or fraction A / B.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## ratio

Maths a quotient of two numbers or quantities
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Factors AF group (n=35) HF group (n=32) Ig(NT-proBNP) 3.40 [+ or -] 0.57 * 4.07 [+ or -] 0.51 * (#) LVEF (%) 56.90 [+ or -] 5.67 * 48.32 [+ or -] 6.00 * (#) LA diameter (mm) 44.95 [+ or -] 9.65 * 45.21 [+ or -] 8.82 * Cardiothoracic ratio 0.62 [+ or -] 0.098 * 0.63 [+ or -] 0.078 * Factors HF-AF group (n=36) Control group (n=32) Ig(NT-proBNP) 4.10 [+ or -] 0.37 * (#) 2.33 [+ or -] 0.86 LVEF (%) 49.92 [+ or -] 6.46 * (#) 61.82 [+ or -] 4.23 LA diameter (mm) 46.69 [+ or -] 8.84 * 37.28 [+ or -] 6.00 Cardiothoracic ratio 0.67 [+ or -] 0.088 * 0.50 [+ or -] 0.01 AF: atrial fibrillation; HF: heart failure; IgNT-proBNP: log N-terminal prohormone brain natriuretic peptide; LVEF: left ventricular ejection fraction; LA: left atrial.
The cardiothoracic ratio was measured as described by Danzer (1): A vertical line is drawn on the frontal film through the spinous procardiac enlargements of the vertebrae.
Left ventricular M-mode echocardiographic measurements and cardiothoracic ratio values are shown according to severity of mitral regurgitation in the Table 1.
There were no statistically significant differences in left ventricular end-systolic diameter, index of left ventricular end- systolic diameter, and index of left ventricular end-diastolic diameter between groups except left ventricular end-diastolic diameter and cardiothoracic ratio values (Table 1).
Among 25 patients with severe regurgitation, cardiothoracic ratio was normal in 20 (80%) patients whereas cardiac enlargement was found in 17 (68%) patients on echocardiography.
The echocardiographic findings and cardiothoracic ratio values are shown in Table 2.
However in this study we found only a weak relation between echocardiographic dimensions and cardiothoracic ratio in patients with severe aortic and mitral regurgitation.
(12) demonstrated that although there was a good correlation between the radiographic total cardiac volume and echocardiographic ventricular volumes; especially left-sided lesions in children; cardiothoracic ratio and cardiac frontal area did not correlate with echocardiographic measurements.
Predictive value of cardiothoracic ratio as a marker of severity of aortic regurgitation and mitral regurgitation.
In the study published in the current issue of the Anatolian Journal of Cardiology, the cardiothoracic ratios of 107 patients with left heart valvular regurgitation were compared with left ventricular dimensions by echocardiography (8).

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