So that is what we call a ratio and it looks like this
The function for the height is

f(0) = 5 cos(0) + 7 = 5 + 7 = 12 (verified)
The period is T = 12 hours.
After 4 hours (t = 4), the height is

A graph of f(t) confirms the answer.
Answer: 4.5 ft
37.5% of 20 is 7.5 so the answer is 37.5%
Answer:
706.85775
Step-by-step explanation:
First you find the volume of the tank
13*3.14159=40.84067
40.84067*75=3063.05025
Then find the volume of both the tank and sleeve
13+3=16
16*3.14159=50.26544
50.26544*75=3769.908
Subtract the original volume with the combined volume
3769.908-3063.05025=706.85775