To find the surface area of the water tank, we need to calculate the area of the two circular bases and the lateral area of the cylinder.
1. Area of the two circular bases:
The radius of the cylinder is half of the diameter, so r = 8 ft / 2 = 4 ft.
The area of one circular base is A = πr^2 = 3.14 x 4^2 = 3.14 x 16 = 50.24 square feet.
Since there are two circular bases, the total area of the two circular bases is 2 x 50.24 = 100.48 square feet.
2. Lateral surface area of the cylinder:
The lateral surface area of a cylinder is given by the formula A = 2πrh, where r is the radius and h is the height.
Plugging in the values, we get A = 2 x 3.14 x 4 x 21.5 = 2 x 3.14 x 86 = 540.64 square feet.
3. Total surface area of the water tank:
The total surface area is the sum of the areas of the two circular bases and the lateral surface area:
Total surface area = 100.48 + 540.64 = 641.12 square feet.
Therefore, the surface area of the water tank is 641.12 square feet.