To calculate the area of a circle, we need to follow the formula to calculate that, which is:

The only value we don't have right now is r, which stands for "radius."
Finding the radius:
To find the radius of this circle, we need to divide the diameter by 2, since the radius is half the size of the diameter.
6/2 = 3
Therfore, our radius is 3.
____________________________________________________
Now we have all the values and we can plug them into our area formula:

Simplify:

Multiply;

Therfore, the answer is 28.26.
___________________________________________________
I hope this helped!
~~~Harsha~~~