What is Ratio: Definition and 1000 Discussions

In mathematics, a ratio indicates how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8∶6, which is equivalent to the ratio 4∶3). Similarly, the ratio of lemons to oranges is 6∶8 (or 3∶4) and the ratio of oranges to the total amount of fruit is 8∶14 (or 4∶7).
The numbers in a ratio may be quantities of any kind, such as counts of people or objects, or such as measurements of lengths, weights, time, etc. In most contexts, both numbers are restricted to be positive.
A ratio may be specified either by giving both constituting numbers, written as "a to b" or "a∶b", or by giving just the value of their quotient a/b. Equal quotients correspond to equal ratios.
Consequently, a ratio may be considered as an ordered pair of numbers, a fraction with the first number in the numerator and the second in the denominator, or as the value denoted by this fraction. Ratios of counts, given by (non-zero) natural numbers, are rational numbers, and may sometimes be natural numbers. When two quantities are measured with the same unit, as is often the case, their ratio is a dimensionless number. A quotient of two quantities that are measured with different units is called a rate.

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  1. J

    MHB Proportions and Equations: Can You Prove a Ratio with this Equation?

    if x/(b+c-a)=y/(c+a-b)=z/(a+b-c) prove that.. x(by+cz-ax)=y(cz+ax-by)=z(ax+by-cz)
  2. A

    Why is C-14 Radioactive Despite Low N/P Ratio?

    Why c - 14 is radio active though n/p ratio is less than 1.5?
  3. H

    Transformers Turn ratio versus Impedence ratio

    Hello, This is my first post, so I hope this is in the right section and format. I've looked all over the web, but I can't find anything that addresses my question clearly. I know that for an ideal transformer to not lose any power, the turn ratio has to be the square root of the...
  4. L

    Help Poisson's Ratio Calculation Problem

    Hi. I can't seem to see where I am going wrong or if i have gone wrong as the answer I got for Poissons Ratio looks incorrect. Can anyone help or point me in the right direction? Thanks. An axial load of 28.5kN is applied to a bar of length280mm, width 38mm and thickness 21mm. After the load...
  5. R

    Stoichiometric ratio calculation

    Dear all, I am trying to synthesis a compound as given the paper below. Can someone help me of how to calculate the stoichiometric ratio and amount of each compound (i.e. Nd pieces, As, Fe, Fe2O3, FeF3 powders) required to prepare the same compound as in that paper. Especially I don’t know...
  6. J

    Obtaining yield stress knowing only Poisson's ratio and UTS?

    Greetings all, I have been trying to find a method of calculating the yield stress for a material when only given; -The loading type (Two bars soldered together in tension) -The dimensions of the shaft and solder (ie thickness of solder, length, cross sectional area) -The Ultimate...
  7. B

    Poissons ratio close-packed spheres

    Hello, See question 7.4 from the link. http://books.google.com/books?id=0N0...ow&w=685&w=800 "Assuming that atoms are hard elastic spheres, show that Poisson's ratio for a close-packed array of spheres is 1/3" I am having trouble explaining the proof for this. I know the that the...
  8. B

    Poissons ratio close-packed spheres

    Hello, See question 7.4 from the link. http://books.google.com/books?id=0N06swAJI0AC&pg=PA338&img=1&zoom=3&hl=en&sig=ACfU3U1qlbfJCRXsRow1xzu7hxEWOjYCow&w=685&w=800 "Assuming that atoms are hard elastic spheres, show that Poisson's ratio for a close-packed array of spheres is 1/3" I...
  9. B

    Time above ground question involving ratio

    In the vertical jump, an athlete starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat the athlete as a particle and let ymax be his maximum height above the floor. To explain why he seems...
  10. V

    Ratio of velocities between proton and electron?

    Homework Statement An electron and a proton are separately placed at rest midway between two oppositely charged metal plates. A) Which way will the electron accelerate? B) Which way will the proton accelerate? C) Which particle, if either, will acquire more kinetic energy just before striking...
  11. C

    MHB Sum series- Prove the equality of ratio and root.

    I found this on the internet, but did not find the proof. Curious to me is that the the ratio and root test have the same conditions. How can i basically prove this equality? \frac{a_{n+1}}{a_{n}} = \sqrt[n]{a_{n}} Thank you!
  12. D

    What is the terminology for this geometry ratio?

    So if we imagine a rectangle. The aspect ratio is width/height. What if you want the ratio of the parallel sides? Is there a terminnology for that ratio?
  13. A

    Ratio of charges in thomson expt

    Homework Statement three particles having charges 1:2:3 produce the same point on the photographic film in the thomson experiment. The masses are in the ratio of a) 1:2:3 b)3:2:1 c) 2:3:1 d) 1:3:2 Homework Equations a = F/m = Eq/m The Attempt at a Solution Since all the...
  14. M

    Kinetic friction ratio problem

    "A driver makes and emergency stop and locks up the brakes of the car, which skids to a stop on dry concrete. Consider the effect of rain on this scenario. If the coefficients of kinetic friction for rubber on dry and wet concrete are μk (dry)=0.80 and μk(wet)=0.50, how much farther would the...
  15. K

    Need some tips in designing a deep ratio helical gear pair

    Hi, For a final drive of a light commercial truck, I have to design a final drive helical gear pair. The expected ratio is 8.2. The centre distance is 134 mm. The input max. torque is 120 Nm. I have sized few combinations. I have a feeling that this ratio is too deep. Pl. share me your...
  16. J

    Chemistry What is the mole ratio of NaOH to C8H8O3 in this reaction?

    Homework Statement We are given the fact that 0.12 mol NaOH reacts with 0.015 mol methyl salicylate (C8H8O3) to form disodium salicylate (C7H4Na2O3). We're asked to calculate the mole ratio of NaOH to C8H8O3, identify the limiting reagents, and find the theoretical yield. Homework Equations...
  17. R

    Solving the Train Length Ratio Puzzle

    Homework Statement Two trains, A and B, are moving towards each other with relative speed 0.8c. The passing of the two trains (from when their fronts align to when their backs align) takes 20% longer as observed from train A as is does as observed from train B. What is the ratio of the length...
  18. maistral

    Ergun Equation reulting to zero pressure ratio

    I was trying to emulate a packed bed reactor, and apparently the pressure midway at the packed column became zero, until my numerical method failed altogether (as the pressure variable in the Ergun is at the denominator). I'd like to be enlightened about one thing - does this phenomena (zero...
  19. R

    The ratio of the gravitational force between electron and proton

    Homework Statement Some of the earliest atomic models held that the orbital velocity of an electron in an atom could be correlated with the radius of the atom. If the radius of the hydrogen atom is 10^−10 m and the electrostatic force is responsible for the circular motion of the electron...
  20. C

    MHB Quit Ratio - Function Question

    So here's the question. In industry, the relationship between wages and the quit ratio of employees is defined to be the percentage of employees that quit within 1 year of employment. The quit ratio of a large restaurant chain that pays its employees the minimum wage \$6.55 per hour was .2 or...
  21. B

    Calculating Moles Ratio of Reactants for Yield f in K Equilibrium

    If I want to calculate the number of moles ratio of reactants which, in a reversible reaction of equilibrium constant K, will give me a certain yield 'f', what is the mathematical definition of the yield in this case? For instance, in the reaction A + B ⇔ C + D, let's say we can denote extent...
  22. R

    Symbols used to represent surface area Ratio in Refrigeration

    Dear all, Does anyone know common symbols used to represent the ratio of two surface areas? The ratio is the surface area of low temp. heat exchanger divided by the total surface area of low and high temp. heat exchanger: AL/AT = area ratio, i want to find or create a symbol for. I would...
  23. Fernando Revilla

    MHB Root or Ratio Test: Interval of Convergence

    I quote a question from Yahoo! Answers I have given a link to the topic there so the OP can see my response.
  24. R

    Refrigeration Heat Exchanger Area Ratio Optimization

    The equation for heat transfer is: 1. Q = U.A.(TL-T1) Where: Q= heat transferred (W). U= overal h.t. coefficient. A= area of heat exhanger (m^2). TL= Temp. of refrigerated space (Kelvin) T1= Low temp. of refrigerant= refrigerant in evaporator (K) I want to eventually find the maximum heat...
  25. siddharth23

    Maximum transmission ratio of a spur gear pair

    WHat is the permissible maximum transmission ratio of a Spur gear pair? I read somewhere that it is 1:5. What wil happen if this is exceeded?
  26. H

    Why does high contact ratio in gear result in inefficiency?

    As titled.This was taught to me in machine design, but I don't see how that makes sense I would think that doesn't matter how many teeths are in contact, since the force between gears are distributed on each pair of teeth in contact, more engaging teeth just mean the friction is distributed to...
  27. L

    Help to find force given a diameter reduction (Poissons Ratio)

    Homework Statement Mild steel bar 40 mm diameter and 100 mm long, subjected to a tensile force along its axis (through central length) Youngs Modulus = 200GN m^-2 Poisson's ratio = 0.3 Calculate the force required to reduce the diameter to 39.99mm (there is also a picture saying Use...
  28. J

    Reply to an old thread on the ratio of parabolas

    I was searching through old threads that had not been replied to and I found one by 'japam' from Feb 6, 2005. After solving it, I realized that the thread was closed so I am reposting it now in case 'japam' is still curious :) -------------------------- His question was: Suppose you have two...
  29. C

    Estimating the damping ratio from the waveform graph

    Homework Statement From the waveform shown below, estimate a) the damping ratio ζ (you may compare response with a standard chart); b) the forced or damped frequency of oscillation; and c) the natural or undamped frequency of oscillation. Homework Equations Since the waveform is under...
  30. E

    When triangles are similar, ratio of corresponding sides is equal.

    "When triangles are similar, ratio of corresponding sides is equal." "When triangles are similar, ratio of corresponding sides is equal." I was wondering if there is any theoretical proof for this statement or is it only experimental?
  31. P

    What Is the Ratio of Baryonic to Dark Matter in the CMB?

    What is the observed DM ratio in CMB ? Is there observational evidence for the DM ratio in the CMB? Other then the info-graph from Wikipedia which I was explained is based on the assumption of DM being the same total amount back then but the mass of relativistic particles was higher. Would...
  32. paulmdrdo1

    MHB Converting a repeating decimal to ratio of integers

    0.17777777777 convert into a ratio.
  33. A

    Polarization: ratio of transmitted to incident intensity

    Homework Statement A beam of unpolarized light is incident on a series of three polarizers as shown. The angle of the transmission axis of each polarizer is indicated by the dashed line, with q1 = 110, q2 =230, and q3 = 370 (all defined relative to vertical). What is the ratio of the...
  34. U

    Find Ratio of Integrals: $\lim_{n \to\infty} I_n/I_{n-2}$

    Homework Statement If I_n = \displaystyle \int^1_0 x^n. \sqrt{1-x^2} dx then \lim_{n \to \infty} \dfrac{I_n}{I_{n-2}} is equal to Homework Equations The Attempt at a Solution Integrating by parts x^n \displaystyle \int \sqrt{1-x^2}dx - \int nx^{n-1} \int \sqrt{1-x^2} dx But...
  35. V

    Has the Proton:Electron Mass Ratio Been Solved Yet?

    Reading my old copy (3rd edition) of H&R's Fundamentals of Physics and it states that no theory can predict the value of the proton:electron mass ratio to date, and that it's a "sure-fire" Nobel Prize problem. Has this been resolved yet? Can't find anything on the web. Thanks in advance.
  36. J

    Limit Ratio Test: Solving $$\sum_{n=1}^{\infty}\frac{1}{2^n}$$

    Homework Statement $$ \sum_{n=1} ^\infty\frac{1} {2^n} $$ Homework Equations The Attempt at a Solution I know just by looking at it that it converges no problem. You do the ratio test and you get something of the form \displaystyle\lim_{n\rightarrow \infty}...
  37. H

    What is the angle of an incline with a ratio of 1:25?

    Hey, I need to calculate the angle of an incline, But they only give me the ratio of 1:25, The only thing i can think of what to do is, 1 / 25 = 0.04 then 100% x 0.04 = 4 degrees, Im i right in asuming this?
  38. Fernando Revilla

    MHB  Use the Ratio Test for Convergence/Divergence

    I quote a question from Yahoo! Answers I have given a link to the topic there so the OP can see my response.
  39. A

    Kinetic energy of two different masses (ratio)

    Homework Statement Two masses, one of 20kg and the other of 40kg, are pushed using the same force on the same distance. What is the ratio of the kinetic energy? (Kinetic energy of 20kg/kinetic energy of 40kg) Homework Equations Ek=mv^2 F=ma v=at The Attempt at a Solution So, I...
  40. D

    Ratio test for math convergence

    Homework Statement show ## \sum \frac{x^{2}}{(1+x^{2})^{n}} ## converges uniformly on R Homework Equations The Attempt at a Solution I know by ratio test it is absolutely convergent for all x in R. I am guessing you use m-test. However I do not really understand how...
  41. C

    Quantum Harmonic oscillator, <T>/<V> ratio

    Homework Statement Consider an electron confined by a 1 dimensional harmonic potential given by ## V(x) = \dfrac{1}{2} m \omega^2 x^2##. At time t=0 the electron is prepared in the state \Psi (x,0) = \dfrac{1}{\sqrt{2}} \psi_0 (x) + \dfrac{1}{\sqrt{2}} \psi_4 (x) with ## \psi_n (x) = \left(...
  42. S

    Propeller Driven Aircraft with Thrust to Weight Ratio Greater than One

    Hello all, this is my first post. I was wondering if any of you could point me in the direction of a source with details on propeller aircraft able to produce a T / W Ratio greater than one. Thank You!
  43. V

    Likelihood Ratio Statistic & P-value

    Homework Statement Homework Equations So far I have only worked on question 1, as I was not able to solve it. The likelihood ratio test statistic is defined as follows: λ = 2 Log(L(theta-hat)/L(theta-hat_0)) Where L is the likelihood function, the product of all the pdfs/pmfs, and theta-hat is...
  44. P

    The ratio between temporal lengths is frame-invariant

    Hi, I am a researcher in (analytical) philosophy. I am writing a paper on the conventionalism vs. objectvism about temporal metric, which is focused on a problem that arises before any relativistic consideration. However, in a note, I just wrote the following "the ratio between temporal lengths...
  45. R

    What is the air-fuel ratio for liquid petrol

    I've been wondering this for a while, I can't figure it out though, it's easy enough for figure it out for petrol vapour, but the problem is with liquids when Googling it, the ratio 14.7:1 is common, but it seems as if that's for pure Octane. if someone could also include the method of...
  46. F

    Ratio test (convergent or divergent?)

    Homework Statement ∞ Ʃ n / 2^n n=1 Homework Equations ratio test lim |a(n+1) / a(n)| n->∞ The Attempt at a Solution I have the answer and the steps its just there's one part I am confused on, first I just apply n+1 to all my n terms, which gives me, ∞ Ʃ...
  47. D

    Signal to Noise ratio calculation

    A 200mv peak to peak sinusoidal signal is applied to an ideal 12 bit A/D converter, for which Vref(v p-p full scale) is 5v. Find signal to noise ratio. This is a problem worked out by one of my lecturer and the answer seems to be 46dB. But I am confused on his method. Is there anyone who...
  48. D

    Ratio of product to difference - terminology?

    Is there a specific mathematical term, which refers to this expression? A * B ------ A - B
  49. R

    Calculating dA/dB ratio for horizontal log?

    In the figure, a 105 kg uniform log hangs by two steel wires, A and B, both of radius 1.25 mm. Initially, wire A was 2.50 m long and 1.80 mm shorter than wire B. The log is now horizontal. Young's modulus for steel is 2.00 × 1011 N/m2. What is the ratio dA/dB? I'm honestly at a loss for how...
  50. 9

    How do I simplify this k/l ratio?

    Homework Statement Simplify this: y = ((k^1/2)/(l^1/4))/((l^1/5)/((k^1/8)) Ideally I would like to make rather than (k/l)/(l/k) simply (k/l) Homework Equations y = ((k^1/2)/(l^1/4))/((l^1/5)/((k^1/8)) The Attempt at a Solution y = (k^3/8)/(l^1/20)
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