Скачать или смотреть Direct proportions

Direct proportion or direct variation is the relation between two quantities where the ratio of the two is equal to a constant value. It is represented by the proportional symbol, ∝.

Direct proportion Examples in Real Life
In our day-to-day life, we observe that the variations in the values of various quantities depending upon the variation in values of some other quantities.

For example: if the number of individuals visiting a restaurant increases, earning of the restaurant also increases and vice versa. If more number of people are employed for the same job, the time taken to accomplish the job decreases.

Direct Proportion Symbol and Constant of Proportionality

The symbol for “direct proportional” is ‘∝’ (One should not confuse with the symbol for infinity ∞). Two quantities existing in direct proportion can be expressed as;

x ∝ y

x/y = k

x = ky

k is a non-zero constant of proportionality.

Where x and y are the value of two quantities and k are a constant known as the constant of proportionality. If x1, y1 is the initial values and x2, y2 are the final values of quantities existing in direct proportion. They can be expressed as,
x1/x2 = y1/y2