Proportional : Directly proportional

Two related quantities x and y are called proportional (or directly proportional) if there exists a constant non-zero number k such that

y = kx

In this case, k is called the proportionality constant of the relation. If y and x are proportional, we often write

y ~ x.

For example, if you travel at a constant speed, then the distance you cover and the time you spend are proportional, the proportionality constant being the speed. Similarly, the amount of force acting on a certain object from the gravity of the Earth at sea level is proportional to the object's mass.

To test whether x and y are proportional, one performs several measurements and plots the resulting points in a Cartesian coordinate system. If the points lie on (or close to) a straight line passing through the origin (0,0), then the two variables are proportional, with the proportionality constant given by the line's slope.

The two quantities x and y are inversely proportional if there exists a non-zero constant k such that

y = k/x

For instance, the number of people you hire to shovel sand is (approximately) inversely proportional to the time needed to get the job done.

See also: proportional font, proportional representation

Common misspelling and questions (FAQ)

irectly-proportional  drectly-proportional  diectly-proportional  dirctly-proportional  diretly-proportional  direcly-proportional  directy-proportional  directl-proportional  directlyproportional  directly-roportional  directly-poportional  directly-prportional  directly-proortional  directly-proprtional  directly-propotional  directly-proporional  directly-proportonal  directly-proportinal  directly-proportioal  directly-proportionl  directly-proportiona  idrectly-proportional  driectly-proportional  dierctly-proportional  dircetly-proportional  diretcly-proportional  direclty-proportional  directyl-proportional  directl-yproportional  directlyp-roportional  directly-rpoportional  directly-porportional  directly-prpoortional  directly-prooprtional  directly-proprotional  directly-propotrional  directly-proporitonal  directly-proportoinal  directly-proportinoal  directly-proportioanl  directly-proportionla  directly-proportiona  ddirectly-proportional  diirectly-proportional  dirrectly-proportional  direectly-proportional  direcctly-proportional  directtly-proportional  directlly-proportional  directlyy-proportional  directly--proportional  directly-pproportional  directly-prroportional  directly-prooportional  directly-propportional  directly-propoortional  directly-proporrtional  directly-proporttional  directly-proportiional  directly-proportioonal  directly-proportionnal  directly-proportionaal  directly-proportionall  eirectly-proportional  sirectly-proportional  xirectly-proportional  rirectly-proportional  cirectly-proportional  rirectly-proportional  firectly-proportional  cirectly-proportional  d8rectly-proportional  durectly-proportional  djrectly-proportional  d9rectly-proportional  dkrectly-proportional  d9rectly-proportional  dorectly-proportional  dkrectly-proportional  di4ectly-proportional  dieectly-proportional  didectly-proportional  di5ectly-proportional  difectly-proportional  di5ectly-proportional  ditectly-proportional  difectly-proportional  dir3ctly-proportional  dirwctly-proportional  dirsctly-proportional  dir4ctly-proportional  dirdctly-proportional  dir4ctly-proportional  dirrctly-proportional  dirdctly-proportional  diredtly-proportional  dirextly-proportional  direftly-proportional  direftly-proportional  direvtly-proportional  direc5ly-proportional  direcrly-proportional  direcfly-proportional  direc6ly-proportional  direcgly-proportional  direc6ly-proportional  direcyly-proportional  direcgly-proportional  directoy-proportional  directky-proportional  direct,y-proportional  directpy-proportional  direct.y-proportional  directpy-proportional  direct;y-proportional  direct.y-proportional  directl6-proportional  directlt-proportional  directlg-proportional  directl7-proportional  directlh-proportional  directl7-proportional  directlu-proportional  directlh-proportional  directly0proportional  directlypproportional  directly[proportional  directly-0roportional  directly-oroportional  directly-lroportional  directly--roportional  directly-;roportional  directly--roportional  directly-[roportional  directly-;roportional  directly-p4oportional  directly-peoportional  directly-pdoportional  directly-p5oportional  directly-pfoportional  directly-p5oportional  directly-ptoportional  directly-pfoportional  directly-pr9portional  directly-priportional  directly-prkportional  directly-pr0portional  directly-prlportional  directly-pr0portional  directly-prpportional  directly-prlportional  directly-pro0ortional  directly-prooortional  directly-prolortional  directly-pro-ortional  directly-pro;ortional  directly-pro-ortional  directly-pro[ortional  directly-pro;ortional  directly-prop9rtional  directly-propirtional  directly-propkrtional  directly-prop0rtional  directly-proplrtional  directly-prop0rtional  directly-propprtional  directly-proplrtional  directly-propo4tional  directly-propoetional  directly-propodtional  directly-propo5tional  directly-propoftional  directly-propo5tional  directly-propottional  directly-propoftional  directly-propor5ional  directly-proporrional  directly-proporfional  directly-propor6ional  directly-proporgional  directly-propor6ional  directly-proporyional  directly-proporgional  directly-proport8onal  directly-proportuonal  directly-proportjonal  directly-proport9onal  directly-proportkonal  directly-proport9onal  directly-proportoonal  directly-proportkonal  directly-proporti9nal  directly-proportiinal  directly-proportiknal  directly-proporti0nal  directly-proportilnal  directly-proporti0nal  directly-proportipnal  directly-proportilnal  directly-proportiohal  directly-proportiobal  directly-proportiojal  directly-proportiojal  directly-proportiomal  directly-proportionql  directly-proportionwl  directly-proportionzl  directly-proportionwl  directly-proportionsl  directly-proportionzl  directly-proportionao  directly-proportionak  directly-proportiona,  directly-proportionap  directly-proportiona.  directly-proportionap  directly-proportiona;  directly-proportiona.  dyrectly-proportional  directly-proportonal  direcyly-proportional  directyly-proportional  directly-proportionals 


Arkwright's heart against that journey by very bad name;--and here on their outward journey her husband had had spent there among uncouth strangers, during a portion of which four months she begged that she might not be taken round by Punt' by the Serapiqui." As to Harry's loving her, there was no doubt Greytown, it is true, is quite as unhealthy as Punt' Arenas, and by boats. There are all manner of difficulties attached to it. is subject to sharper fatigue while it lasts. Journeying by this so mounted he makes his way through the vast primeval forests down is of course true; but it is simply a track, and during nine months bellies. Then, when the river has been reached, the traveller seats Serapiqui, into the San Juan River, and down along the San Juan till side. At Greytown he waits for the steamer which will carry him his connoisseur in disagreeables of every kind who can say with any week's sojourn. For a full month Mr. Arkwright would not give way to his.