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2 years ago

Given: MNFD is a trapezoid.

Mathematics

1 answer:

Rama09 [41]2 years ago

6 0

A trapezoid with legs MN = FD is an isosceles trapezoid.
An isosceles trapezoid has diagonals that are congruent, therefore: MF = ND.
A quadrilateral with diagonals congruent and perpendicular is a square.
In a square, the height coincides with the side.
The area of a square is given by A = s²
Therefore, the area of MNFD is h²

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Nadia built a robot to filter air and water efficiently. She expects the robot to filter more than 343 liters of

Natasha2012 [34]

Answer:

The correct option is;

B. The robot filters the expected amount of air and water, but it doesn't use the expected amount of energy

Step-by-step explanation:

The given requirements are;

Volume of air and water to be filtered by the robot = 343 liters

The amount of energy consumed by the robot < 49 joules

The number of minutes the robot filters air and water to filter more than 343 liters = 12A + 8W > 343

The number of minutes the robot filters air and with less than 49 Joule of energy = 3A + 4W < 49

Given that filtering air takes 20 minutes, filtering water takes 15 minutes, we have;

To filter more than 343 liters, we have

12*20 + 8*15 = 360 > 343

The robot meets the amount of air and water requirement

To filter with less than 49 joules we have

3*20 + 4*15 = 120 > 49

Therefore, the robot does not meet the energy requirement

The correct option is the robot filters the expected amount of air and water, but it doesn't use the expected amount of energy.

7 0

2 years ago

A random sample of 9 wheels of cheese yielded the following weights in pounds has a sample mean of 20.90 and a sample variance o

Ronch [10]

Answer:

$2.002 \leq \sigma^2 \leq 11.365$

Step-by-step explanation:

1) Data given and notation

s represent the sample standard deviation

$s^2$ represent the sample variance

n=9 the sample size

Confidence=90% or 0.90

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^9 (x_i -\bar x)^2}{n-1}}
The sample variance given was [tex]s^2=3.45$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=9-1=8$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical values.