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3 years ago

Need help on #6 step by step I'm so confused how this works I always get stuck

Mathematics

1 answer:

inna [77]3 years ago

6 0

To find the variable x, set the two outside equations equal to each other because all sides are equal
x+13=3x+3
13=2x+3
10=2x
x=5

then to find h, you set the equation equal to 90 because that's how many degrees it is
2h-45=90
2h=135
h=67.5

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Solve the following equation. Then place the correct number in the box provided. 6x - 8 = 16

uysha [10]

6x-8=16
6x-8+8=16+8
6x=24
6x=24
— —
6 6
X= 4

8 0

3 years ago

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In the square below, the two semi-circles are congruent. Find the area of the shaded region. If necessary, round your answer to

Jobisdone [24]

Let's start with the area of the square
$area \: square = s \times s = 8 \times 8 = 64$
now let's subtract the are of the two half circles.
two half circles are the same as one circle, and we know that the diameter of the circle is 8 (same as the side of a square) so it's radius is 8/2= 4 inches

$area \: circle = \pi {r}^{2} = \pi \times {4}^{2} = 16\pi$
now we just subtract and our answer is

$64 - 16\pi = 64 - 16 \times (3.14) = 13.73$

3 0

3 years ago

PLS HELP ILL MARK BRAINLIST !!

andreev551 [17]

Answer:

Last option it should be

6 0

3 years ago

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The manufacturer of hardness testing equipment uses steel-ball indenters to penetrate metal that is being tested. However, the

kumpel [21]

Answer:

Check the explanation

Step-by-step explanation:

Let X denotes steel ball and Y denotes diamond

$\bar{x_1}$ = 1/9( 50+57+......+51+53)

=530/9

=58.89

$\bar{x_2}$ = 1/9( 52+ 56+....+ 51+ 56)

=543/9

=60.33

difference = d =(60.33- 58.89)

=1.44

$s^2=1/n\sum xi^2 - n/(n-1)\bar{x}^2$

s12 = 1/9( 502+572+......+512+532) -9/8 (58.89)2

=31686/8 - 9/8( 3468.03)

=3960.75 - 3901.53

=59.22

s1 = 7.69

s22 = 1/9( 522+ 562+....+ 512+ 562) -9/8 (60.33)2

=33295/8 - 9/8 (3640.11)

=4161.875 - 4095.12

=66.75

s2 =8.17

sample standard deviation for difference is

s= $\sqrt{[(n1-1)s_1^2+ (n2-1)s_2^2]/(n1+n2-2)}$

= $\sqrt{[(9-1)*59.22+ (9-1)*66.75]/(9+9-2)}$

= $\sqrt{1007.76/16}$

=7.93

sd = $s*\sqrt{(1/n1)+(1/n2)}$

= $7.93*\sqrt{(1/9)+(1/9)}$

=7.93* 0.47

=3.74

For 95% confidence level $Z (\alpha /2)$ =1.96

confidence interval is

$d\pm Z(\alpha /2)*s_d$

=(1.44 - 1.96* 3.75 , 1.44+1.96* 3.75)

=(1.44 - 7.35 , 1.44 + 7.35)

=(-2.31, 8.79)

There is sufficient evidence to conclude that the two indenters produce different hardness readings.

3 0

3 years ago

Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviat

drek231 [11]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

Step-by-step explanation:

For this case we have the following probability distribution given:

X 0 1 2 3 4 5

P(X) 0.031 0.156 0.313 0.313 0.156 0.031

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

We can verify that:

$\sum_{i=1}^n P(X_i) = 1$

And $P(X_i) \geq 0, \forall x_i$

So then we have a probability distribution

We can calculate the expected value with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

6 0

3 years ago