It doesn't matter improper fractions are aloud
The area of a circle is given by
whereas the circumference is given by
If we want these two values to be (numerically) the same we have to set and solve for the radius:
So, one (trivial) solution is . A circle with radius 0 is just a point, and so both area and circumference are zero.
The other solution is . In fact, you have
There are 100 centimeters in 1 meter. If you convert 3.25 meters to centimeters, then you should get 325 centimeters.
To find the volume of the model of the Earth, you will use the formula (rule) for finding the volume of a sphere.
You will divide the diameter by 2 to get the radius. 6.5/2 = 3.25 m
V = 4/3 x pi x r^3
= 4/3 x 3.14 x 3
V = 143.72 cubic meters
The volume of the model is approximately 143.72 cubic meters.