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2 years ago

What is the lateral area of this regular octagonal pyramid? 84.9 cm² 120 cm² 169.7 cm² 207.8 cm²

Mathematics

2 answers:

ahrayia [7]2 years ago

3 0

Like jdoe0001 answered with 8[1/2(5)(6 $8[ \frac{1}{2} (5)(6 \sqrt{2} )]$ if you solve the equation he/she gave you then you get 167.70562748. so your answer will be 167.7 cm^2

Lesechka [4]2 years ago

3 0

Check the picture below.

the lateral area, namely the area of the sides, in this case will be the area of all the triangular faces of the OCTAgonal pyramid, OCTA=8, so there are 8 of them.

now, each triangular face, has a base of 5 and a height of 6√2, so we simply get the area of each triangle and sum them up,

$\bf \stackrel{\textit{area of the 8 triangles}}{8\left[ \cfrac{1}{2}(5)(6\sqrt{2}) \right]}
$

You might be interested in

The edges of three squares are joined together to form a right triangle with legs of lengths R & S and a hypotenuse of lengt

dezoksy [38]

Answer:

$R^{2} + S^{2} = T^{2}$

Step-by-step explanation:

the pythagorean theorem

8 0

2 years ago

Mr and Mrs Smith buy tickets for themselves and their four children.

Aneli [31]

The cost of an adult ticket is £6 more than that of a child ticket, so will be denoted by c+6. Now, we are told that the cost of four child tickets and two adult tickets is £40.50, so we can put this in an equation and solve for c:
(c+6)+(c+6)+c+c+c+c=40.50
6c+12=40.50
6c=28.50
c=4.75
Therefore the cost of a child's ticket (c) is £4.75 and the cost of an adult ticket (c+6) is £10.75.

4 0

1 year ago

Find the correlation coefficient of the line of best fit for the points (-3,-40), (1,12), (5,72), (7,137). Explain how you guy y

vodka [1.7K]

Answer:

r = 0.9825; good correlation.

Step-by-step explanation:

One formula for the correlation coefficient is

$r = \dfrac{n\sum{xy} - \sum{x} \sum{y}}{\sqrt{n\left [\sum{x}^{2}-\left (\sum{x}\right )^{2}\right]\left [\sum{y}^{2}-\left (\sum{y}\right )^{2}\right]}}$

The calculation is not difficult, but it is tedious.

1. Calculate the intermediate numbers

We can display them in a table.

x y xy x² y²

-3 -40 120 9 1600

1 12 12 1 144

5 72 360 25 5184

7 137 959 49 18769

Σ = 10 181 1451 84 25697

2. Calculate the correlation coefficient

$r = \dfrac{n\sum{xy} - \sum{x} \sum{y}}{\sqrt{\left [n\sum{x}^{2}-\left (\sum{x}\right )^{2}\right]\left [n\sum{y}^{2}-\left (\sum{y}\right )^{2}\right]}}\\\\= \dfrac{4\times 1451 - 10\times 181}{\sqrt{[4\times 84 - 10^{2}][4\times25697 - 181^{2}]}}\\\\= \dfrac{5804 - 1810}{\sqrt{[336 - 100][102788 - 32761]}}\\\\= \dfrac{3994}{\sqrt{236\times70027}}\\\\= \dfrac{3994}{\sqrt{16526372}}\\\\= \dfrac{3994}{4065}\\\\= \mathbf{0.9825}$

The closer the value of r is to +1 or -1, the better the correlation is. The values of x and y are highly correlated.

3 0

1 year ago

Company F sells fabrics known as fat quarters, which are rectangles of fabric created by cutting a yard of fabric into four piec

jeka94

Answer:

a) Y 0 1 2

P(Y) 0.58 0.23 0.11

b) mean= 0.45, S.D= 0.6718

c) mean= 1.285, S.D= 8.74

Step-by-step explanation:

a) The following table shows the probability distribution of X:

X 0 1 2 3 4 or more

P(X) 0.58 0.23 0.11 0.05 0.03

Defect >2 = cannot be sold

Y = the number of defects on a fat quarter that can be sold by Company F.

Y = defect that can be sold

Y = Defect less or equal to 2 = 0,1,2

Probability distribution of the random variable Y:

Y 0 1 2

P(Y) 0.58 0.23 0.11

b) mean of Y (μ)

μ = Σ x*P(Y)

= (0*0.58) +(1*0.23)+(2*0.11)

= 0+0.23+0.22 = 0.45

Standard deviation of Y = σ

σ = Σ√(x-mean)^2*P(Y)

= Σ√[(x- μ )^2*P(Y)]

= √[(0-0.45)^2*0.58+ (1-0.45)^2*0.23 + (2-0.45)^2*0.11]

= √[0.11745 + 0.069575 +0.264275

= √(0.4513

σ = 0.6718

Company G:

σ for defect that be sold = 0.66

μ for defect that be sold = 0.40

Difference between μ of F and μ of G

= 0.45-0.40 = 0.05

Difference between σ of F and σ of G

= 0.67-0.66 = 0.01

Selling price of fat quarter without defect = $5

Discount per defect = $1.5

Selling price per defect = 5-1.5 = $3.5

Discount per 2 defect = $1.5*2 = $3

Selling price per defect = 5-3 = $2

Since defect to be sold cannot be greater than 2, let Y = 5,3,2

Probability distribution of the selling price Y:

Y 5 3 2

P(Y) 0.58 0.23 0.11

μ = (5*0.58) +(3.5*0.23)+(2*0.11)

μ = 2.9+0.805+0.22 =1.285

σ = Σ√[(x- μ )^2*P(Y)]

σ = √[(5-1.285)^2*0.58+ (3-1.285)^2*0.23 + (2-1.285)^2*0.11]

σ = 8.00+0.68+0.06 = 8.74

7 0

2 years ago

A teacher collected information from a class of 25 students about the time, in hours, they spent studying the previous week and

amm1812

Answer:

Correlation will not change.

Correlation coefficient = -0.72

Step-by-step explanation:

We are given the following in the question:

Correlation coefficient between hours spent studying and hours spent on the Internet = -0.72

Properties of correlation coefficient:

Correlation is a technique that help us to find or define a relationship between two variables.
It is a measure of linear relationship between two quantities.
It is not affected by the units of the variable or change in units of the variable.

Thus, if the units of each variable is changed from hours to minutes, the correlation coefficient remains the same between minutes studying and minutes spent on the Internet.

5 0

2 years ago