Answer:
314 ft²
Step-by-step explanation:
Data provided in the question:
Depth (height) of the pool = of its radius
let the radius be 'r' ft
thus,
Depth (height) of the pool, h = ft
Volume of the pool = 1570 ft³
also,
Volume of cylinder = πr²h
thus,
1570 ft³ = πr²h
or
1570 ft³ =
or
3140 = 3.14 × r³ [ π = 3.14 ]
or
r³ = 1000 ft³
or
r = 10 ft
Thus,
Area of the bottom surface = πr²
= 3.14 × 10²
= 314 ft²
<u>Answer:</u>
The Ranking Percentile is (B) 97.5%
<u>Explanation :</u>
To find the percentile rank we need to find the z- score. After finding the z-score match this value with the corresponding value in z-score table.
Formula to find the z-score
Z-score=
Substituting the values in the above equation, we find
Z-score= =2
So, the Z-score is +2
Now, the corresponding value of Z-score 2 in the table is 0.9772
or the percentile score is 97.72 ~ 97.5 .