<span>Although two cylinders may have equal diameters, their volumes are not necessarily equal, as the volume of a cylinder is dependent also on the cylinder's height. The same holds true for cones. Spheres, however, are, by nature, proportional. Therefore, if two spheres have the same diameter, they also have the same volumes.</span>
<span>You did not include the equations that you want to assess whether they can be used to solve for the radius (r).
Likely, the equation of the circumference, C = 2*Pi*r is included, if so => r = C / (2*Pi).
If you round Pi to 3.14, the equation may be written r = C / 6.28.</span>
18 divided by 6 is 3
when you add 3 with 4 it gives you 7
7 is your total answer
2+2=4 and 4+4=8 and 8+8=16
