Answer:
Perimeter is 17.07
Step-by-step explanation:
We know that DF = EF = 5 cm, since D and E are the midpoints of AC and AB, both of which are 10 cm in length.
We need to use the Pythagorean theorem to get the length of DE.
![DE = \sqrt{5^{2} +5^{2}}=\sqrt{50} = 7.07\\](https://tex.z-dn.net/?f=DE%20%3D%20%5Csqrt%7B5%5E%7B2%7D%20%2B5%5E%7B2%7D%7D%3D%5Csqrt%7B50%7D%20%20%3D%207.07%5C%5C)
So the perimeter of DEF is 5 + 5 + 7.07 = 17.07
We need to find out how many adults must the brand manager survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage.
From the given data we know that our confidence level is 90%. From Standard Normal Table we know that the critical level at 90% confidence level is 1.645. In other words,
.
We also know that E=5% or E=0.05
Also, since,
is not given, we will assume that
=0.5. This is because, the formula that we use will have
in the expression and that will be maximum only when
=0.5. (For any other value of
, we will get a value less than 0.25. For example if,
is 0.4, then
and thus,
.).
We will now use the formula
![n=(\frac{Z_{Critical}}{E})^2\hat{p}(1-\hat{p})](https://tex.z-dn.net/?f=%20n%3D%28%5Cfrac%7BZ_%7BCritical%7D%7D%7BE%7D%29%5E2%5Chat%7Bp%7D%281-%5Chat%7Bp%7D%29%20)
We will now substitute all the data that we have and we will get
![n=(\frac{1.645}{0.05})^2\times0.5(1-0.5)](https://tex.z-dn.net/?f=%20n%3D%28%5Cfrac%7B1.645%7D%7B0.05%7D%29%5E2%5Ctimes0.5%281-0.5%29%20%20)
![n=(32.9)^2\times0.25](https://tex.z-dn.net/?f=%20n%3D%2832.9%29%5E2%5Ctimes0.25%20)
![n=270.6025](https://tex.z-dn.net/?f=%20n%3D270.6025%20)
which can approximated to n=271.
So, the brand manager needs a sample size of 271
Answer:
x = +√30
Step-by-step explanation:
Please write 30 = x squared as 30 = x^2.
If x^2 = 30, there are two solutions: x = +√30 and x = -√30.
Several possible answers are given. x=30−−√ is closest to the correct one, but must be written as x = √30. Please ask someone how to find the "√" operator in Brainly. Or, just write "sqrt( )" instead.
The population in 2040 of the town can be solved using the formula
F = P( 1 -I)^n
Where F is the future population
P is the present population
I is the decline rate
N is the number of years
F = 22,000(1-0.028)^39
<span>F = 7268</span>
The answer is c. Because all you need to know is to find the other leg and find the perimeter of the whole thing.