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Westkost [7]
4 years ago
11

una dintre fetele laterale ale unei piramide patrulatere regulate este triunghi echilateral cu latura de 7cm. Calculati aria baz

ei piramidei consideratei
Mathematics
1 answer:
masha68 [24]4 years ago
3 0

Answer:

21.27 cm^2

Step-by-step explanation:

Pentru a calcula aria bazei, putem folosi formula lui Heron Matematic aceasta este;

A = √s (s-a) (s-b) (s-c)

Unde s = (a + b + c) / 2

a, b, c se referă la laturile triunghiului

A = (7 + 7 + 7) / 2 = 21/2 = 10,5

A = √10,5 (10,5-7) (10,5-7) (10,5-7)

A = √10,5 (3,5) (3,5) (3,5)

A = √450.1875

A = 21.2176 cm ^ 2, care este de aproximativ

21.22 cm ^ 2

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Peter is trying to buy fencing for the perimeter of his garden. His garden is in the shape of a rectangle with a length of 2(x+6
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Given dimensions of a rectangular garden are:

length = 2(x+6) feet

width = 3.5x feet

using the distributive property on length we get, length = 2x+12

Perimeter of a rectangle is 2(length+width)

So, P = 2(2x+12+3.5x)

Solving it we get,

P = 2(5.5x +12)   ..............adding like terms

P = (2\times5.5)+(2\times12) .............multiplying and adding

P = 11x+24

So, perimeter is 11x+24 feet. This value of fencing will be needed.

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3 years ago
Write the equation of the line with a<br> slope of -2 and passes through (4, -1).
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7 0
3 years ago
A single gram of a certain metallic substance has 0.52 g of copper and 0.25 g of zinc the remaining portion of the substance is
andrezito [222]
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3 years ago
Julio was paid1.4times his normal hourly rate for each hour he works over 30 hours in a week. Last week he worked 35 hours and e
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5 0
4 years ago
Suppose that a local TV station conducts a survey of a random sample of 120 registered voters in order to predict the winner of
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Answer:

a) The 99% CI for the true proportion of voters who prefer the Republican candidate is (0.3658, 0.6001). This means that we are 99% sure that the true population proportion of all voters who prefer the Republican candidate is (0.3658, 0.6001).

b) The upper bound of the confidence interval is above 0.5 = 50%, which meas that the candidate can be confidence of victory.

Step-by-step explanation:

Question a:

In a sample with a number n of people surveyed with a probability of a success of \pi, and a confidence level of 1-\alpha, we have the following confidence interval of proportions.

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which

z is the z-score that has a p-value of 1 - \frac{\alpha}{2}.

Sample of 120 registered voters in order to predict the winner of a local election. The Democrat candidate was favored by 62 of the respondents.

So 120 - 62 = 58 favored the Republican candidate, so:

n = 120, \pi = \frac{58}{120} = 0.4833

99% confidence level

So \alpha = 0.01, z is the value of Z that has a p-value of 1 - \frac{0.01}{2} = 0.995, so Z = 2.575.  

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b. If a candidate needs a simple majority of the votes to win the election, can the Republican candidate be confident of victory? Justify your response with an appropriate statistical argument.

The upper bound of the confidence interval is above 0.5 = 50%, which meas that the candidate can be confidence of victory.

8 0
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