What does it mean when we say we say direct and inverse(indirect) proportion ???

A direct and inverse proportion is used to show how the quantities and amount are related to each other. For example, if we say, a is proportional to b, then it is represented as 'a∝b' and if we say, a is inversely proportional to b, then it is denoted as 'a∝1/b'.

What is the direct proportion?

Direct proportion is the relationship between two variables whose ratio is equal to a constant value.

Example

The term direct proportion means that two (or more) quantities increase or decrease in the same ratio. For example, in the purple paint mixture, the ratio of blue to red of 4:3. This does not necessarily mean we every mixture would have 4 red and 3 blue cans.

Formula

In mathematical statements, it can be expressed as y = kx. This reads as “y varies directly as x” or “y is directly proportional as x” where k is constant in the equation.

What is the indirect proportion?

Inverse proportion occurs when one value increases and the other decreases.

Example

More workers on a job would reduce the time to complete the task. They are inversely proportional.

Formula

The equation for inverse proportion is x y = k or x = k/ y. Therefore, for finding the value of the constant k, you can use the known values and then use this formula to calculate all the unknown values.

use formula for the circle a=3.14

step-by-step explanation: