In the formula, area of circle , the numerical constant of the expression is ________.
Determine the numeric constant in the formula of the area of a circle.
According to the definition of a constant, a constant is a quantity that has a fixed value.
In the formula of the area of a circle, there are two quantities first one is radius and the second one is .
As we know, radius varies from circle to circle but the value of is fixed that is .
Therefore, the numerical constant of the expression is .