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MAVERICK [17]
3 years ago
14

Find the value of x.

Mathematics
1 answer:
Roman55 [17]3 years ago
3 0

Answer:

\huge\boxed{x=\sqrt{21}}

Step-by-step explanation:

ΔABD and ΔBCD are similar (AAA).

Therefore the corresponding sides are in proportion:

\dfrac{BD}{CD}=\dfrac{AD}{BD}

Substitute

BD=x;\ CD=3;\ AD=7

\dfrac{x}{3}=\dfrac{7}{x}              <em>cross multiply</em>

(x)(x)=(3)(7)\\\\x^2=21\to x=\sqrt{21}

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the area of a rectangular decks is 680 square feet. the decks width is 17 feet. what is its perimeter ?
Ket [755]
The perimeter is 114 square feet. To solve this, first you divide 680 by 17, which equals 40. So the length is 40. The formula for perimeter is 2L+2W. This means you take the length and multiply it by 2, and do the same for the width, then add them together. So the equation would be:
2(40)+2(17)=Perimeter
80+34=Perimeter 
The final answer is 114 square feet.
4 0
3 years ago
Please help with this math problem! Will give brainliest! :)
tangare [24]

Answer:

9

Step-by-step explanation:

All triangles (3 sided polygons) have angles added up to 180, so we can do the following:

(7x-1) + (7x+8) + (5x+2) = 180° <em>- equation</em>

7x-1 + 7x+8 + 5x+2 = 180° <em>- "distribute"</em>

19x - 1 + 8 + 2 = 180°<em> - combine the x terms</em>

19x + 9 = 180° <em>- combine the integer terms</em>

19x = 171 <em>- subtract 9 form both sides</em>

x = 9 <em>- divide both sides by 19</em>

4 0
2 years ago
The mean of a sequence of n numbers is m. If we split the sequence into two sequences of lengths n1 and n2 and compute their mea
Furkat [3]

The mean of a sequence of numbers is the average.

The true statement is: \mathbf{mn = m_1 \times n_1 + m_2 \times n_2}

The given parameters are:

\mathbf{Mean = m}

\mathbf{Size = n}

The mean of a dataset is calculated as:

\mathbf{Mean = \frac{\sum x}{Size}}

So, we have:

\mathbf{m = \frac{\sum x}{n}}

Multiply both sides by m

\mathbf{\sum x = mn}

When the sequence is split into two, we have:

\mathbf{\sum x_1 = m_1\times n_1}

\mathbf{\sum x_2 = m_2\times n_2}

Where:

\mathbf{\sum x_ = \sum x_1 + \sum x_2}

So, we have:

\mathbf{mn = m_1 \times n_1 + m_2 \times n_2}

Hence, the true statement is: \mathbf{mn = m_1 \times n_1 + m_2 \times n_2}

Read more about mean and averages at:

brainly.com/question/16217700

8 0
3 years ago
3a + 3b is equivalent to 3(a + 2b). <br> A true<br> B false
Sunny_sXe [5.5K]

Answer:

B-false

Step-by-step explanation:

It is false because where the 2 is, has to be 3, other wise it won't make sense. Because it will not equal the same thing.

4 0
3 years ago
a caterer received an order to prepare 120 servings of salad for a banquet. Each serving will weigh 4 ounces. so far the caterer
Ugo [173]
To easier digest this question, we can multiply the 120 servings by 4 ounces to make it into a common unit of measurement. This way, we can compare ounces with ounces instead of ounces to servings.
We then have 480 servings, and the poor caterer only has 60 ounces. We can put that into a fraction, 60/480. From here, things get slightly easier. All we have to do is make it into a fraction we can digest, which would be 1/8. We can turn that fraction into a decimal by simply dividing. We have 0.125.
Since we are changing from a decimal into a percent, we have to move the decimal point two places to the right. We have out final answer of 12.5%.
6 0
3 years ago
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