1) The area of a circle is given by

where r is the radius of the circle. In this problem, we are told that the area is

so we can rearrange the previous equation to calculate the radius:

And now we can find the circumference, by using the formula:

Therefore, the correct answer is D. 75.3984 meters.
2) The volume of a cube is given by:

where L is the length of the edge. In this problem, L=6 cm, therefore the volume of the cube is

and so, the correct answer is A. 216 cu. cm.