To find the volume of a spherical fish tank, we can use the formula for the volume of a sphere:
\[ V = \frac{4}{3} \pi r^3 \]
where \( V \) is the volume and \( r \) is the radius of the sphere.
Given that the radius \( r \) is 3 inches, we can plug this value into the formula:
\[ V = \frac{4}{3} \pi (3)^3 \]
Calculating \( (3)^3 \):
\[ (3)^3 = 27 \]
Now substituting back into the volume formula:
\[ V = \frac{4}{3} \pi (27) \]
\[ V = \frac{108}{3} \pi \]
\[ V = 36 \pi \]
Now we can use the value of \( \pi \) (approximately 3.14):
\[ V \approx 36 \times 3.14 \approx 113.04 , \text{in}^3 \]
This value is very close to 113.10 in³. Thus, if the tank is filled to the top, the volume of water in the tank is approximately:
\[ \text{Volume} \approx 113.10 \text{ in}^3 \]
So the correct answer is 113.10 in³.