Answer:
Formula for circumference: 2 x pie(3.14 or 22/7) x radius(half of diameter or already given radius). Area of a circle: pie(3.14 or 22/7) x radius squared
Radius: 3, 6 is diameter and half of that is 3.
3 x 3.14 x 2 = 18.84 <------ circumference
3.14 x 3^2
3.14 x 9 = 28.26 <------ area of the circle