Direct Variation Formula

Direct variation formula

The two variables are said to have a direct variation with one another when one quantity is directly reliant on the other, such as when one quantity grows in relation to the other and vice versa. In this type of direct variation relation, one is a constant multiple of the other.

Direct variation is referred to a relationship between the two variables where one is a constant multiple of the other. They are said to be in proportion because one variable changes the other.

For example, if a is directly proportional to d then the equation will be given as 

a= kd, where k is a constant.

The ratio of the variables that are in direct variation always remains the same. This direct variation can be represented in various mathematical forms. In equation form, since the ratio of y to x never changes, y and x vary directly 

The Direct Variation Formula is expressed as,

y = kx

Let us take some examples of the Direct variation formula

1. Suppose y = 72 when x = 8 and y varies directly as x. Note down a direct variation equation that relates x and y with each other

Solution:

Let us use the direct variation formula y = kx.

Replace y with 72 and x with 8.

72 = k (8)

or, k = 72/8

k = 9.

Therefore, the direct variation equation will be y = 9x.

2. When the values are y = 98 when x = 14, and y varies directly as x then calculate the direct variation equation that relates x with y.

Solution:

Let us use the direct variation formula y = kx.

Replace y with 98 and x with 14.

98 = k (14)

or, k = 98/14

k = 7.

Therefore, the direct variation equation will be y = 7x.