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2 years ago

Given: ΔABC, AC = BC, AB = 3 CD ⊥ AB , CD = square root of 3 Find: AC

Mathematics

1 answer:

quester [9]2 years ago

3 0

Answer:

AC = 2.30

Step-by-step explanation:

Given: ΔABC, AC = BC, AB = 3 CD ⊥ AB , CD = $\sqrt{3}$ .

Since CD ⊥ AB, thus CD divides AB into two equal parts.

From ΔACD, applying the Pythagoras theorem;

$AC^{2}$ = $AD^{2}$ + $CD^{2}$

= $1.5^{2}$ + $(\sqrt{3}) ^{2}$

= 2.25 + 3

= 5.25

AC = $\sqrt{5.25}$

= 2.2913

∴ AC = 2.30

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The New Mexico Division of Fish and Wildlife keeps track of the silvery minnow population in the Rio Grande River. They tagged 5

sattari [20]

Answer:

279 silvery minnow

Step-by-step explanation:

Number of Silvery Minnows initially tagged = 54

Number of minnows captured = 62

Number of tagged minnows in captured ones = 12

Remember that in the very beginning there were no tagged minnows. 54 minnows were captured, tagged and released. This means, there are total 54 tagged minnows in the entire population. Lets say there are x number of minnows in total.

So, in x minnows, 54 are tagged ones.

When 62 minnows are captured, only 12 are tagged ones and remaining are un-tagged. Since, the minnows were randomly captured, we can develop a proportion from this case to estimate the total population of minnows in the Rio Grande River.

Ratio of tagged minnows to total population must be equal to the ratio of captured tagged minnows in total captured minnows.

i.e.

$54 : x = 12 : 62\\\\ \frac{54}{x} = \frac{12}{62}\\\\ 62(54)=12x\\ \\ x = 279$

This means, there were 279 silvery minnows in the Rio Grande River.

3 0

2 years ago

What is the equation of a line that is parallel to the line 2x + 5y = 10 and passes through the point (–5, 1)? Check all that ap

Bond [772]

So the right options are:

$y=-\frac{2}{5}x-1$

$2x+5y = -5$

$y-1=-\frac{2}{5}(x+5)$

Further explanation:

Given equation of line is:

2x+5y=10

We have to convert it into point-slope form

$2x+5y=10\\5y=-2x+10\\Dividing\ both\ sides\ by\ 5\\y=-\frac{2}{5}x+\frac{10}{5}\\y=-\frac{2}{5}x+2$

The co-efficient of x is the slope of the line

So,

$m= -\frac{2}{5}$

As the required line is parallel to given line, it will also have same slope.

Let m1 be the slope of required line

Then the line will be:

$y=m_1x+b$

Putting the value of slope

$y=\frac{2}{5}x+b$

Putting (-5,1) in the equation to find the value of b

$1=-\frac{2}{5}(-5)+b\\1=2+b\\b=1-2\\b=-1$

Putting the values of slope and b in equation

$y=-\frac{2}{5}x-1$

Multiplying the whole equation by 5 will give us:

5y = -2x-5

2x+5y = -5

Another form of equation of line is Point-slope form

$y-y_1=m(x-x_1)$

Putting the values of slope and point in the equation, we get

$y-1=-\frac{2}{5}(x+5)$

So the right options are:

$y=-\frac{2}{5}x-1$

$2x+5y = -5$

$y-1=-\frac{2}{5}(x+5)$

Keywords: Point-Slope form, Parallel lines

Learn more about point slope form at:

#LearnwithBrainly

4 0

2 years ago

Read 2 more answers

A math teacher tells her students that eating a healthy breakfast on a test day will help their brain function and perform well

kogti [31]

Answer:

Step-by-step explanation:

Hello!

To test the claim that eating a healthy breakfast improves the performance of students on their test a math teacher randomly asked 46 students what did they have for breakfast before they took the final exam and classified them as:

<u>Group 1</u>: Ate healthy breakfast

X₁: Number of students that ate a healthy breakfast before the exam and earned 80% or higher.

n₁= 26

<u>Group 2: </u>Did not eat healthy breakfast

X₂: Number of students that did not eat a healthy breakfast before the exam and earned 80% or higher.

n₂= 20

After the test she counted the number of students that got 80% or more in the test for each group obtaining the following sample proportions:

p'₁= 0.50

p'₂= 0.40

The parameters of study are the population proportions, if the claim is true then p₁ > p₂

And you can determine the hypotheses as

H₀: p₁ ≤ p₂

H₁: p₁ > p₂

α: 0.05

$Z= \frac{(p'_1-p'_2)-(p_1-p_2)}{\sqrt{p'(1-p')[\frac{1}{n_1} +\frac{1}{n_2}] } } }$ ≈N(0;1)

pooled sample proportion: $p'= \frac{x_1+x_2}{n_1+n_2} =\frac{13+8}{46} = 0.46$

$Z_{H_0}= \frac{(0.5-0.4)-0}{\sqrt{0.46(1-0.46)[\frac{1}{26} +\frac{1}{20}] } } }= 0.67$

p-value: 0.2514

The decision rule is:

If p-value ≤ α, reject the null hypothesis.

If p-value > α, do not reject the null hypothesis.

The p-value: 0.2514 is greater than the significance level 0.05, the test is not significant.

At a 5% significance level you can conclude that the population proportion of math students that obtained at least 80% in the test and had a healthy breakfast is equal or less than the population proportion of math students that obtained at least 80% in the test and didn't have a healthy breakfast.

So having a healthy breakfast doesn't seem to improve the grades of students.

I hope this helps!

5 0

2 years ago

Which equation can pair with x + 2y = 5 to create an inconsistent system?

Charra [1.4K]

X + 2y = 5
x = 5 - 2y

2x + 4y = 3
2(5-2y) + 4y = 3
10 - 4y + 4y = 3
10 ≠ 3

5x + 2y = 3
5(5-2y) + 2y = 3
25 - 10y + 2y = 3
-8y = 3 - 25
-8y = -22
y = -22/-8
y = 2.75

6x + 12y = 30
6(5-2y) + 12y = 30
30 -12y + 12y = 30
30 = 30

3x + 4y = 8
3(5-2y) + 4y = 8
15 - 6y + 4y = 8
-2y = 8 - 15
-2y = -7
y = -7/-2
y = 3.5

An inconsistent system is a system of equation that has NO SOLUTIONS.

2x + 4y = 3 is the equation to be paired with x + 2y = 50 to create an inconsistent system.

6 0

2 years ago

Read 2 more answers

"How much do students pay, on average, for textbooks during the first semester in college? From a random sample of 400 students

dezoksy [38]

Answer: The margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.

Step-by-step explanation:

Since we have given that

Sample size = 400

Mean = $357.75

Standard deviation = $37.89

At 95% confidence level, z = 1.96

We first find the margin of error.

Margin of error is given by

$z\times \dfrac{\sigma}{\sqrt{n}}\\\\=1.96\times \dfrac{37.89}{\sqrt{400}}\\\\=3.71$

95% confidence interval would be

$\bar{x}\pm \text{margin of error}\\\\=357.75\pm 3.71\\\\=(357.75-3.71,357.75+3.71)\\\\=(354.04,361.46)$

Hence, the margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.

7 0

2 years ago