B=7 I showed my work so I hope it helps!
Answer:
a) h = 123/x^2
b) S = x^2 +492/x
c) x ≈ 6.27
d) S'' = 6; area is a minimum (Y)
e) Amin ≈ 117.78 m²
Step-by-step explanation:
a) The volume is given by ...
V = Bh
where B is the area of the base, x^2, and h is the height. Filling in the given volume, and solving for the height, we get:
123 = x^2·h
h = 123/x^2
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b) The surface area is the sum of the area of the base (x^2) and the lateral area, which is the product of the height and the perimeter of the base.

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c) The derivative of the area with respect to x is ...

When this is zero, area is at an extreme.
![0=2x -\dfrac{492}{x^2}\\\\0=x^3-246\\\\x=\sqrt[3]{246}\approx 6.26583](https://tex.z-dn.net/?f=0%3D2x%20-%5Cdfrac%7B492%7D%7Bx%5E2%7D%5C%5C%5C%5C0%3Dx%5E3-246%5C%5C%5C%5Cx%3D%5Csqrt%5B3%5D%7B246%7D%5Capprox%206.26583)
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d) The second derivative is ...

This is positive, so the value of x found represents a minimum of the area function.
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e) The minimum area is ...

The minimum area of metal used is about 117.78 m².
Answer:
18 jars can be filled completely.
Step-by-step explanation:
7L=7000ml
1 jar contain 375 ml
375ml can be filled in 1 jar
375ml=1 jar
1 ml = 1/375 jar
7000 ml = 7000× 1/375 jar
7000ml= 18.67 jar
hence 18 jars can be filled completely.
Answer:
It should be reported as 20.648%
Step-by-step explanation:
Since we have 2 different observed values hence we shall use an average of the 2 values to report the result
Thus value is 
As we can see that the least count of our observations is upto 3 decimal places hence we have to report a result upto only 3 decimal places thus we need to round off the fourth decimal place thus the digit shall be increased by 1 since we have to drop off 5 and the digit before 5 is 7 which is an odd number.
Thus the result shall be 20.648%
Answer: 5.3
Step-by-step explanation: Do 9.8 (Friend swim depth) - 4.5 (dolphin jump height) to get your answer.