The volume of the cylinder is

Where:
r is the radius of the base of the cylinder
h is the height of the cylinder
Since the cylinder is 8 inches tall, then
h = 8 inches
Since it is 4 inches across the lid, then
The diameter of the base is 4 inches
Divide it by to get the radius of it, then
r = 2 inches
Now, substitute them in the rule above

We can use pi = 3.14, then

The volume of the soup is 100.48 inches^3