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3 years ago

Geometry help please? 4 questions. Thanks!

Mathematics

1 answer:

wel3 years ago

7 0

Question 1:

Statement Reasons
m∠ABD + m∠DBC = m∠ABC Angle addition postulate
60° + 40° = m∠ABC Substitution Property of equality
100° = m∠ABC Simplpifying
∠ABC is an obtuse angle Definition of obtuse angle

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Question 2:

Statement Reasons
AC = BD Given
AC = BC + BD Segment addition postulate
AB + BC = BC + CD Addition property of equality

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Question 3:

Angle congruence postulate

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Question 4:

Segment congruence postulate

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$800 principal earning 7%, compounded annually, after 4 years

xz_007 [3.2K]

800(1+7)∧4
it will be $1048.63

4 0

3 years ago

In a study of parents' perceptions of their children's size, researchers asked parents to estimate their youngest child's height

tatyana61 [14]

Answer:

Test statistic t=6.505

P-value=0

Step-by-step explanation:

This is a hypothesis test for the population mean.

The claim is that parents tend to underestimate their youngest child's size.

Then, the null and alternative hypothesis are:

$H_0: \mu=0\\\\H_a:\mu> 0$

The significance level is assumed to be 0.05.

The sample has a size n=39.

The sample mean is M=7.5.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=7.2.

The estimated standard error of the mean is computed using the formula:

$s_M=\dfrac{s}{\sqrt{n}}=\dfrac{7.2}{\sqrt{39}}=1.153$

Then, we can calculate the t-statistic as:

$t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{7.5-0}{1.153}=\dfrac{7.5}{1.153}=6.505$

The degrees of freedom for this sample size are:

$df=n-1=39-1=38$

This test is a right-tailed test, with 38 degrees of freedom and t=6.505, so the P-value for this test is calculated as (using a t-table):

$P-value=P(t>6.505)=0$

As the P-value (0) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that parents tend to underestimate their youngest child's size.

5 0

2 years ago

Find the length of the indicated side.

Ne4ueva [31]

Hello

DEF and IKL , equilateral =>

DE = 5x-12 = 3x-4

5x-3x= -4+12

2x= 8

x=4

DE = 5x-12 = 20-12 = 8

KL = 3x+24 = 10x+3

24 -3 = 10x-3x

21 = 7x

x= 21/7 = 3

KJ = 10x+3 = 30+3 = 33

6 0

2 years ago

If 90 percent of automobiles in Orange County have both headlights working, what is the probability that in a sample of eight au

Marta_Voda [28]

Answer:

$P(X \geq 7) = P(X=7) +P(X=8)$

And we can find the individual probabilities using the probability mass function

$P(X=7)=(8C7)(0.9)^7 (1-0.9)^{8-7}=0.3826$

$P(X=8)=(8C8)(0.9)^8 (1-0.9)^{8-8}=0.4305$

And replacing we got:

$P(X \geq 7) = P(X=7) +P(X=8)=0.3826 +0.4305=0.8131$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest "number of automobiles with both headligths working", on this case we now that:

$X \sim Binom(n=8, p=0.9)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

And for this case we want to find this probability:

$P(X \geq 7) = P(X=7) +P(X=8)$

And we can find the individual probabilities using the probability mass function

$P(X=7)=(8C7)(0.9)^7 (1-0.9)^{8-7}=0.3826$

$P(X=8)=(8C8)(0.9)^8 (1-0.9)^{8-8}=0.4305$

And replacing we got:

$P(X \geq 7) = P(X=7) +P(X=8)=0.3826 +0.4305=0.8131$

7 0

3 years ago

Read 2 more answers

Allyson walked 10.8 km to the school. If 1 mile = 1.6 km, about how many miles did she walk?

seropon [69]

Answer:

According to my calculations, 1.6 goes into 10.8 a total of 6 times with a remainder of 1.1999999999999993. If you continue the long division beyond the decimal point, the result would be 6.75.

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers