Circles: Area

1. Find the area of a circle with a radius of 12 inches.

2. Find the area of a circle with a diameter of 8 inches.

3. Find the area of the circle: 

4. Find the area of the circle: 

5. If the area of a circle is $81\pi$ feet, what is the length of the radius?

6. Find the area of a circular amphitheater if the length across its center is 450 feet.

7. If a circular room has a radius of 25 feet, what is the area of the room?

8. If a circular field has a diameter of 30 feet, what is the area of the field?

9. If the area of a hot tub is 50.24 feet, how long is the radius of the hot tub?

10. If you need to paint a circular sign that has a diameter of 12 inches, what is the size of the area that needs to be covered in paint?