
Andrew P. answered 05/18/21
Undergraduate at UC Berkeley, 3 years Geometry tutoring experience
The easiest way to approach this problem is to solve it as if the question were asking about a full sphere, then divide by 2 (since it is hemispherical).
The first step is to find the volume of the sphere. We can use the equation:
Vs = 4/3 * pi * r3
Where Vs is the volume of a sphere.
We can calculate the radius by dividing the diameter by 2: 19 ft/2 = 9.5 feet.
Thus, the volume is:
Vs = 4/3 * pi * r3
Vs = 4/3 * pi * (9.5)3
Vs = 3591.364 ft3
Since the tank is hemispherical, rather than spherical, we divide this volume by 2 to find the volume of the hemisphere:
Vh = Vs/2 where Vh is the volume of the hemisphere and Vs is the volume of the sphere
Vh = 3591.364 ft3/2 = 1795.682 ft3
Now, we multiply the volume by the density of the water to find the total weight of the water in the full tank:
62.4 pounds/ft3 * 1795.682 ft3 = 112050.5569 pounds
The cubic feet cancel, leaving us with just pounds.
The final answer is thus 112050.5569 pounds, or, rounded to the hundredths place, 112050.56 pounds.
Dylan B.
thank you05/18/21