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3 years ago

Use the figure above to identify a pair of similar triangles, then find the scale factor. The image is not drawn to scale.

Mathematics

2 answers:

natali 33 [55]3 years ago

4 0

Answer:

Option C.

Step-by-step explanation:

we know that

If two triangles are similar, then the ratio of its corresponding sides is proportional and its corresponding angles are congruent

In this problem triangles HEF and EGE are similar

because

$EF/GF=HF/EF$

substitute the values

$\frac{\sqrt{3}}{1}=\frac{3}{\sqrt{3}}\\ \\3=3$

Is true

The sides are proportional

and

∠HFE=∠GFE

∠EHF=∠GEF

∠HEF=∠EGF

The angles are congruent

The scale factor is equal to

$EF/GF$

$\frac{\sqrt{3}}{1}$

ch4aika [34]3 years ago

4 0

Answer:

Option C

Step-by-step explanation:

Two triangles are similar if they have at least 2 equal angles

Note that the HEF triangle has angles of 90 °, 60 ° and 30 °

Note that the EGF triangle has angles of 90 ° and 30 ° so the third angle must be 60 °

Then HEF and EGF are similar triangles.

By definition for similar triangles it is satisfied that if they have sides of length a, b, c and a ', b' c' then

$\frac{a}{a'}=\frac{b}{b'}=\frac{c}{c'}=k$

Where the constant k is known as "scale factor"

In this case

$\frac{HF}{EF}=\frac{HE}{EG}=\frac{FE}{GF}=k$

$k=\frac{3}{\sqrt{3}}=\frac{2\sqrt{3}}{2}=\frac{\sqrt{3}}{1}=\sqrt{3}$

$\frac{FE}{GF}=\frac{\sqrt{3}}{1}$

$\sqrt{3}:1$

The answer is Option C

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Modern medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x

Anna11 [10]

Answer:

a) Figure attached

b) $y=1.31 x +98.57$

c) The correlation coefficient would be r =0.47719

d) $y=1.31 x +98.57=1.31*21 + 98.57 =126.08$

Step-by-step explanation:

(a) Draw a scatter diagram for the data.

See the figure attached

(b) Find x, y, b, and the equation of the least-squares line. (Round your answers to three decimal places.) x =__ y =__ b =__ y =__ + __x

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=6576-\frac{300^2}{14}=147.429$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=38186-\frac{300*1773}{14}=193.143$

And the slope would be:

$m=\frac{193.143}{147.429}=1.31$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{300}{14}=21.429$

$\bar y= \frac{\sum y_i}{n}=\frac{1773}{14}=126.643$

And we can find the intercept using this:

$b=\bar y -m \bar x=126.643-(1.31*21.429)=98.571$

So the line would be given by:

$y=1.31 x +98.57$

(c) Find the sample correlation coefficient r and the coefficient of determination r?2. (Round your answers to three decimal places.)

n=14 $\sum x = 300, \sum y = 1773, \sum xy=38186, \sum x^2 =6576, \sum y^2 =225649$

And in order to calculate the correlation coefficient we can use this formula:

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

$r=\frac{14(38186)-(300)(1773)}{\sqrt{[14(6576) -(300)^2][14(225649) -(1773)^2]}}=0.9534$

So then the correlation coefficient would be r =0.47719

What percentage of variation in y is explained by the least-squares model? (Round your answer to one decimal place.)

The % of variation is given by the determination coefficient given by $r^2$ and on this case $0.47719^2 =0.2277$ , so then the % of variation explaines is 22.8%.

(d) If a female baby weighs 21 pounds at 1 year, what do you predict she will weigh at 30 years of age? (Round your answer to two decimal places.) ___ lb

So we can replace in the linear model like this:

$y=1.31 x +98.57=1.31*21 + 98.57 =126.08$