Answer:
That statement is true, but you do not always need the two.
Let's say that we had a problem, given the radius is 5, and we have to find the diameter.
First step is to define A
[tex]A = \pi r^2[/tex]
Second, redefine r as the actual radius to avoid confusion.
[tex]r = 5[/tex]
Third, set up an equation with the given values where you are multiplying pi by the radius.
[tex]\pi r^2 = \pi *r^2[/tex]
Fourth but not least, get the actual value.
[tex]\pi * r^2 = 79[/tex] rounded to nearest whole number