Step-by-step explanation:
Volume of a sphere is
[tex] \frac{4}{3} \pi {r}^{3} [/tex]
plug in 70 ft for the radius to get 1,436,755 cubic ft then divide that by 4 since the prompt describes a quarter sphere, giving you a tank volume of 359,189 cubic ft.
Volume of a cylinder is
[tex]\pi {r}^{2} h[/tex]
from the second prompt we know the tanks are identical since they are said to be congruent which means the hight and radius are the same. Plug in 120 f for h and 35 ft for r to get the volume of a cylinder and then divide that by 2 to get the volume of a single tank. the volume of both tanks would be
[tex]\pi {35}^{2} (120) = 461,814[/tex]
To show tank model is a sixth of the original so you divide the radius by 6 and perform the same calculation as in the first portion of the problem ro get the volume a quarter sphere
[tex] \frac{4}{3} \pi {( \frac{70}{6} )}^{3} = 6,652 \: {ft}^{3} [/tex]
To get the percentage of the model relative to the original you divide the models volume by the full scale volume
[tex] \frac{6652}{1436755} \times 100 = 0.46[/tex]
which is less than 1% of the full scale volume.