Solution:
Given that;
You can measure the diameter of a spherical object by putting the object on a flat surface and placing blocks or books on either side of the object.
The ruler is used to measure the distance between the blocks or books.
The length on the ruler is 7.3 inches, i.e. the diameter of the sphere is the length on the ruler
Hence, the diameter of the sphere is 7.3 inches
To find the radius, r, the formula is

To find the volume, V, of a sphere, the formula is

Substitute the value of r into the formula above

Hence, the volume is 203.7 in³