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Flura [38]
3 years ago
8

Ragazzi vi presento questo problema è mi piacerebbe se riusciate ad aiutarmi a risolverlo:"Calcola il perimetro di un trapezio i

soscele sapendo che ha l'area di 660 m(quadrati), l'altezza di 12 m e la base minore di 20 m.​

Mathematics
2 answers:
Drupady [299]3 years ago
7 0

Facendo riferimento alla figura allegata, partiamo dall'area: sappiamo che

A=\dfrac{(B+b)h}{2}

dove B e b sono rispettivamente la base maggiore e la base minore, mentre h è l'altezza.

Sostituendo i valori nella formula, possiamo ricavare la base maggiore:

660=\dfrac{12(B+20)}{2}=6(B+20)

Dividendo entrambi i membri per 6 abbiamo

110=B+20 \iff B=90

A questo punto abbiamo

B-b=2AH \iff 2AH=70 \iff AH=35

Conoscendo sia AH sia l'altezza BH, possiamo usare il teorema di Pitagora per calcolare il lato obliquo AB:

AB=\sqrt{AH^2+BH^2}=\sqrt{1225+144}=37

Ricapitolando, abbiamo:

  • AB=37
  • BC=20
  • CD=37 (per simmetria, è uguale ad AB perché il trapezio è isoscele)
  • AD=90

La somma dei quattro lati di darà il perimetro. Ciao!

iren [92.7K]3 years ago
3 0

Answer:

per il vertice basta che usi la formula: V (-b/2a ; - delta/4a)

asse x : -b/2a

Step-by-step explanation:

here is your answer to your work plz rate me the most brainlest

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3 years ago
Slope=-3 goes through (1,2) whats the equation
dedylja [7]

Hi student, let me help you out! :)

..............................................................................................................................................

We are asked to find the equation of the line, using the given information:

\star~\mathrm{-3}, which is the slope

\star~\mathrm{(1,2)} which is a point that the line contains

\triangle~\fbox{\bf{KEY:}}

  • The slope is the number before x, in the form \mathtt{y=mx+b}.

Since "m" is the slope, and we're given what the slope is, we can substitute -3 for m:

\dag~\mathtt{y=-3x+b}

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

Now, we need to find the y intercept, "b", of the line.

Here's how it's done:

Remember the point that the line contains, (1,2)?

Well, its y-coordinate is 2; so what we do is substitute 2 for y:

\dag~\mathtt{2=-3x+b}

Also, its x-coordinate is 1, so we substitute 1 for x:

\dag~\mathtt{2=-3(1)+b}

Now, solve for b:

\dag~\mathtt{2=-3+b}

Add 3 to both sides:

\dag~\mathtt{2+3=b}

Thus, we have

\dag~\mathtt{5=b}

Thus, the equation of the line is:

\bigstar\underline{\boxed{\mathtt{y=-3x+5}}}

Hope it helps you out! :D

Ask in comments if any queries arise.

#StudyWithBrainly

~Just a smiley person helping fellow students :)

\overline{\underline{~~~~~~~~~~~~~~~~~~~~~~~~~~}}

3 0
2 years ago
The quality-control manager at a compact flourescent light bulb factory wants to test the claim that the mean life of a large sh
MAXImum [283]

Answer:

a. At the 0.05 level of significance,  there is evidence that the mean life is different from 6,500 hours.

b. The p value= ≈ 0.00480 for z- test which is less than 0.05 and H0 is rejected .

The p value= 0.006913 for t- test which is less than 0.05 and H0 is rejected for 49 degrees of freedom.

c. CI [6583.336 ,6816.336]

d.  The range of CI [6583.336 ,6816.336] tells that the cfls having a different mean life lie in this range.

Step-by-step explanation:

Population mean = u= 6500 hours.

Population standard deviation = σ=500 hours.

Sample size =n= 50

Sample mean =x`=  6,700 hours

Sample standard deviation=s=  600 hours.

Critical values, where P(Z > Z) =∝ and P(t >) =∝

Z(0.10)=1.282  

Z(0.05)=1.645  

Z(0.025)=1.960  

t(0.01)(49)= 1.299

t(0.05)= 1.677  

t(0.025,49)=2.010

Let the null and alternate hypotheses be

H0: u = 6500 against the claim Ha: u ≠ 6500

Applying Z test

Z= x`- u/ s/√n

z= 6700-6500/500/√50

Z= 200/70.7113

z= 2.82=2.82

Applying  t test

t= x`- u /s/√n

t= 6700-6500/600/√50

t= 2.82

a. At the 0.05 level of significance,  there is evidence that the mean life is different from 6,500 hours.

Yes we reject H0  for z- test as it falls in the critical region,at the 0.05 level of significance, z=2.82 > z∝=1.645

For t test  we reject H0   as it falls in the critical region,at the 0.05 level of significance, t=2.82 > t∝=1.677 with n-1 = 50-1 = 49 degrees of freedom.

b. The p value= ≈ 0.00480 for z- test which is less than 0.05 and H0 is rejected .

The p value= 0.006913 for t- test which is less than 0.05 and H0 is rejected for 49 degrees of freedom.

c. The 95 % confidence interval of the population mean life is estimated by

x` ±  z∝/2  (σ/√n )

6700± 1.645 (500/√50)

6700±116.336

6583.336 ,6816.336

d. The range of CI [6583.336 ,6816.336] tells that the cfls having a different mean life lie in this range.

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3 years ago
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tensa zangetsu [6.8K]
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Please answer this correctly
melomori [17]

Answer:

4 days

Step-by-step explanation:

there are 8 pints in a gallon

6 0
3 years ago
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