Final answer:
The surface area of the spherical storage tank with a radius of 3.5 ft is approximately 154 ft².
Step-by-step explanation:
To determine the surface area of a spherical storage tank with a radius of 3.5 ft, we can use the formula A = 4πr², where A is the surface area and r is the radius.
Substituting the given radius value into the formula, we have A = 4π(3.5 ft)² = 4π(12.25 ft²) = 49π ft². To round the answer to 3 significant digits, we can use the approximate value of π as 3.14.
Therefore, the surface area of the spherical storage tank is approximately 49(3.14) ft² = 153.86 ft². Rounded to 3 significant digits, the surface area is 154 ft².