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3 years ago

LABC measures 90° and ZABD measures 25. What is the measurement of ZDBC?

Mathematics

1 answer:

makkiz [27]3 years ago

5 0

Answer: The measurement of angle DBC is 65 degrees

Step-by-step explanation:

Line BD splits ABC into two angles ABD and DBC.

If ABC is 90 then the measures of ABD + DBC will be 90. Since we know the measure of ABD we can make this equation and solve it

$90=25+x\\90-25=25+x-25\\65=x$

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A. 2x+5=23<br> B. x+2+5=23<br> C. x+x+5=23<br> D. 5x+2=23

storchak [24]

Answer:

Step-by-step explanation:

lucky guess

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3 years ago

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What is the volume of this square-based pyramid with a base length of 6 feet and a height of 10 feet?

bulgar [2K]

Answer:

60 or 90

Step-by-step explanation:

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3 years ago

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3x=5x-9 pls help ?!!?!?!?!?!?!?!?!??!!?1/

lbvjy [14]

Answer: x = 4.5

Step-by-step explanation:

1) Reorder the terms:

3x = -9 + 5x

2) Solving

3x = -9 + 5x

3) Solving for variable 'x'.

4) Move all terms containing x to the left, all other terms to the right.

5) Add '-5x' to each side of the equation.

3x + -5x = -9 + 5x + -5x

6) Combine like terms: 3x + -5x = -2x

-2x = -9 + 5x + -5x

7) Combine like terms: 5x + -5x = 0

-2x = -9 + 0

-2x = -9

8) Divide each side by '-2'.

x = 4.5

9) Simplifying

x = 4.5

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3 years ago

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Kendrick received 24 fewer e-mails than he did on Thursday. If he received a total of 126 e-mails on those two days, how many di

telo118 [61]

E+(e-24)=126

2e-24=126

2e=150

e=75

So (s)he recieved 75 and 75-24=51 emails on those days.

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3 years ago

4. A random variable X has a mean of 10 and a standard deviation of 3. If 2 is added to each value of X, what will the new mean

Ede4ka [16]

Adding 2 to each value of the random variable $X$ makes a new random variable $X+2$ . Its mean would be

$E[X+2]=E[X]+E[2]=E[X]+2$

since expectation is linear, and the expected value of a constant is that constant. $E[X]$ is the mean of $X$ , so the new mean would be

$E[X+2]=10+2=12$

The variance of a random variable $X$ is

$V[X]=E[X^2]-E[X]^2$

so the variance of $X+2$ would be

$V[X+2]=E[(X+2)^2]-E[X+2]^2$

We already know $E[X+2]=12$ , so simplifying above, we get

$V[X+2]=E[X^2+4X+4]-12^2$

$V[X+2]=E[X^2]+4E[X]+4-12^2$

$V[X+2]=(V[X]+E[X]^2)+4E[X]-140$

Standard deviation is the square root of variance, so $V[X]=3^2=9$ .

$\implies V[X+2]=(9+10^2)+4(10)-140=9$

so the standard deviation remains unchanged at 3.

NB: More generally, the variance of $aX+b$ for $a,b\in\mathbb R$ is

$V[aX+b]=a^2V[X]+b^2V[1]$

but the variance of a constant is 0. In this case, $a=1$ , so we're left with $V[X+2]=V[X]$ , as expected.

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3 years ago