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3 years ago

Help help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mathematics

2 answers:

insens350 [35]3 years ago

8 0

Answer:

there are 3 isosceles triangles

explanation:

triangles A B and D are isosceles

hram777 [196]3 years ago

4 0

Answer:

I am pretty sure it is the 3rd one

(In geometry, an isosceles triangle is a triangle that has two sides of equal length. And i think 3 of them are an isosceles triangle)

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-3x-y=9

Lina20 [59]

Answer:

D: no solution

...because none of the answers work for both of the equations when you plug in the x and y values

4 0

3 years ago

Find the area of a quadrilateral ABCD in which AB = 3 cm, BC = 4 cm, CD = 4 cm, DA = 5 cm and AC = 5 cm.

melamori03 [73]

Answer:

$6+2\sqrt{21}\:\mathrm{cm^2}\approx 15.17\:\mathrm{cm^2}$

Step-by-step explanation:

The quadrilateral ABCD consists of two triangles. By adding the area of the two triangles, we get the area of the entire quadrilateral.

Vertices A, B, and C form a right triangle with legs $AB=3$ , $BC=4$ , and $AC=5$ . The two legs, 3 and 4, represent the triangle's height and base, respectively.

The area of a triangle with base $b$ and height $h$ is given by $A=\frac{1}{2}bh$ . Therefore, the area of this right triangle is:

$A=\frac{1}{2}\cdot 3\cdot 4=\frac{1}{2}\cdot 12=6\:\mathrm{cm^2}$

The other triangle is a bit trickier. Triangle $\triangle ADC$ is an isosceles triangles with sides 5, 5, and 4. To find its area, we can use Heron's Formula, given by:

$A=\sqrt{s(s-a)(s-b)(s-c)}$ , where $a$ , $b$ , and $c$ are three sides of the triangle and $s$ is the semi-perimeter ( $s=\frac{a+b+c}{2}$ ).

The semi-perimeter, $s$ , is:

$s=\frac{5+5+4}{2}=\frac{14}{2}=7$

Therefore, the area of the isosceles triangle is:

$A=\sqrt{7(7-5)(7-5)(7-4)},\\A=\sqrt{7\cdot 2\cdot 2\cdot 3},\\A=\sqrt{84}, \\A=2\sqrt{21}\:\mathrm{cm^2}$

Thus, the area of the quadrilateral is:

$6\:\mathrm{cm^2}+2\sqrt{21}\:\mathrm{cm^2}=\boxed{6+2\sqrt{21}\:\mathrm{cm^2}}$

4 0

3 years ago

B to the eighth power multiplied by b to the fourth power

scZoUnD [109]

U just add the exponents.

b^8 x b^4 = b^12

hope this helps :)

7 0

3 years ago

Suppose a research firm conducted a survey to determine the average amount of money steady smokers spend on cigarettes during a

olchik [2.2K]

Answer:

option (b) 0.0228

Step-by-step explanation:

Data provided in the question:

Sample size, n = 100

Sample mean, μ = $20

Standard deviation, s = $5

Confidence interval = between $19 and $21

Now,

Confidence interval = μ ± $z\frac{s}{\sqrt n}$

thus,

Upper limit of the Confidence interval = μ + $z\frac{s}{\sqrt n}$

$21 = $20 + $z\frac{5}{\sqrt{100}}$

z = 2

Now,

P(z = 2) = 0.02275 [From standard z vs p value table]

P(z = 2) ≈ 0.0228

Hence,

the correct answer is option (b) 0.0228

3 0

3 years ago

A statistic is said to be unbiased if

xxMikexx [17]

Answer:

A statistic is said to be unbiased if the mean of its sampling distribution is equal to the true value of the parameter being estimated.

Step-by-step explanation:

A parameter is a number that describes the population.

A statistic is a number that describes a sample.

A statistic used to estimate a parameter is unbiased if the mean of its sampling distribution is exactly equal to the true value of the parameter being estimated. For example, the mean of a sample is an unbiased estimate of the mean of the population from which the sample was drawn.

A statistic is biased if its expected value is not equal to the parameter.

8 0

3 years ago