Variable

Is a symbol for a number we don’t know yet. X is the variable in the term 4X.

The “letters” in an equation are the variables.

A variable is a symbol part of an equation or next to a number that we don’t know the value of yet

The variable nature of letters' sizes makes them very difficult to manage.

Example 1

$a^2+9^2=100$

In the above equation “a” is the variable.

Example 2

$a^2+b^2=c^2$

In the above equation a, b and c are all variables.

Example 3

$136=\pir^2$

In the above equation r is the variable.