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2 years ago

I don’t know how to do these questions so help plz

Mathematics

2 answers:

mars1129 [50]2 years ago

5 0

Answer:

the anser is no.b that is 30°

ryzh [129]2 years ago

3 0

Answer:

90°

Step-by-step explanation:

There's are supplementary angles at point C. These are two angles that add up to 180°. We know this because a straight line makes 180° on both sides. Since we know that the first angle is 150°, we can determine the angle a point C is 30°. This is shown by:

180-150=30

So now we know 1 angle and the other two angles are put into like terms (in this case, multiples of x). It is known that the sum of all angles in a triangle equates to 180°. Using this information we can set up a simple equation.

$3x+2x+30=180$

Combining like terms, we get:

$5x+30=180$

Isolating x, we get:

$5x=150$

Dividing both sides by 5, we get:

$x=30$

So now we can use this x-value to determine the angle that is being asked. It is shown that angle ABC is equal to 3x. Using the x value we just calculated, we get a final answer of:

$3x=3(30)=90$

Therefore, the answer is 90°. Hope this helps!

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The probability that two people have the same birthday in a room of 20 people is about 41.1%. It turns out that

salantis [7]

Answer:

a) Let X the random variable of interest, on this case we know that:

$X \sim Binom(n=20, p=0.411)$

This random variable represent that two people have the same birthday in just one classroom

b) We can find first the probability that one or more pairs of people share a birthday in ONE class. And we can do this:

$P(X\geq 1 ) = 1-P(X$

And we can find the individual probability:

$P(X=0) = (20C0) (0.411)^0 (1-0.411)^{20-0}=0.0000253$

And then:

$P(X\geq 1 ) = 1-P(X$

And since we want the probability in the 3 classes we can assume independence and we got:

$P= 0.99997^3 = 0.9992$

So then the probability that one or more pairs of people share a birthday in your three classes is approximately 0.9992

Step-by-step explanation:

Previous concepts

A Bernoulli trial is "a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is conducted". And this experiment is a particular case of the binomial experiment.

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".

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:

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

Solution to the problem

Part a

Let X the random variable of interest, on this case we know that:

$X \sim Binom(n=20, p=0.411)$

This random variable represent that two people have the same birthday in just one classroom

Part b

We can find first the probability that one or more pairs of people share a birthday in ONE class. And we can do this:

$P(X\geq 1 ) = 1-P(X$

And we can find the individual probability:

$P(X=0) = (20C0) (0.411)^0 (1-0.411)^{20-0}=0.0000253$

And then:

$P(X\geq 1 ) = 1-P(X$

And since we want the probability in the 3 classes we can assume independence and we got:

$P= 0.99997^3 = 0.9992$

So then the probability that one or more pairs of people share a birthday in your three classes is approximately 0.9992

4 0

3 years ago

I’m discovering that her family had 70% risk of heart attack Aaron took the treadmill testTo check her own potential of having a

zvonat [6]

Taking a test doesn't lessen your risk of a heart attack

4 0

3 years ago

Find an equation for the perpendicular bisector of the line segment whose endpoints

TEA [102]

Answer:

y= -2x -8

Step-by-step explanation:

I will be writing the equation of the perpendicular bisector in the slope-intercept form which is y=mx +c, where m is the gradient and c is the y-intercept.

A perpendicular bisector is a line that cuts through the other line perpendicularly (at 90°) and into 2 equal parts (and thus passes through the midpoint of the line).

Let's find the gradient of the given line.

$\boxed{gradient = \frac{y1 -y 2}{x1 - x2} }$

Gradient of given line

$= \frac{1 - ( - 5)}{3 - ( - 9)}$

$= \frac{1 + 5}{3 + 9}$

$= \frac{6}{12}$

$= \frac{1}{2}$

The product of the gradients of 2 perpendicular lines is -1.

(½)(gradient of perpendicular bisector)= -1

Gradient of perpendicular bisector

= -1 ÷(½)

= -1(2)

= -2

Substitute m= -2 into the equation:

y= -2x +c

To find the value of c, we need to substitute a pair of coordinates that the line passes through into the equation. Since the perpendicular bisector passes through the midpoint of the given line, let's find the coordinates of the midpoint.

$\boxed{midpoint = ( \frac{x1 + x2}{2} , \frac{y1 + y2}{2}) }$

Midpoint of given line

$= ( \frac{3 - 9}{2} , \frac{1 - 5}{2} )$

$= ( \frac{ - 6}{2} , \frac{ - 4}{2} )$

$= ( - 3 , - 2)$

Substituting (-3, -2) into the equation:

-2= -2(-3) +c

-2= 6 +c

c= -2 -6 (-6 on both sides)

c= -8

Thus, the equation of the perpendicular bisector is y= -2x -8.

5 0

3 years ago

11. A roofer calculates his bid price using the formula P = 1.85s + 4.2f, where s is the area of the roof in square feet and f i

storchak [24]

Replace f with 190, replace P with 4148 and solve for s:

4148 = 1.85s + 4.2(190)

Simplify:

4148 = 1.85 + 798

Subtract 798 from both sides:

3350 = 1.85s

Divide both sides by 1.85:

s = 1,810.81

Rounded to nearest square foot = 1811 square feet.

8 0

3 years ago

Read 2 more answers

In triangle , side and the perpendicular bisector of meet in point , and bisects . If and , what is the area of triangle

stich3 [128]

In triangle ABC, side AC and the perpendicular bisector of BC meet in point D, and BD bisects ∠ABC。 If AD = 9 and DC = 7, 145–√5 is the area of a triangle.

I supposed here that [ABD] is the perimeter of ▲ ABD.

As BD is a bisector of ∠ABC ,

ABBC=ADDC=97

Let ∠B=2α

Then in isosceles △DBC

∠C=α

BC=2∗DC∗cosα=14cosα

Thus AB=18cosα

The Sum of angles in △ABC is π so

∠A=π−3α

Let's look at AC=AD+DC=16 :

AC=BCcosC+ABcosA

16=14cos2α+18cosαcos(π−3α)

[1]8=7cos2α−9cosαcos(3α)

cos(3α)=cos(α+2α)=cosαcos(2α)−sinαsin(2α)=cosα(2cos2α−1)−2cosαsin2α=cosα(4cos2α−3)

With [1]

8=cos2α(7−9(4cos2α−3))

18cos4−17cos2α+4=0

cos2α={12,49}

First root lead to α=π4 and ∠BDC=π−∠DBC−∠C=π−2α=π2 . In such case ∠A=π−∠ABD−∠ADB=π4, and △ABD is isosceles with AD=BD. As △DBC is also isosceles with BD=DC=7, AD=7≠9.

Thus first root cos2α=12 cannot be chosen and we have to stick with the second root cos2α=49. This gives cosα=23 and sinα=5√3.

The area of a triangle ABD=12h∗AD where h is the distance from B to AC.

h=BCsinC=14cosαsinα

Area of triangle ABD=145–√5

= 145–√5.

Incomplete question please read below for the proper question.

In triangle ABC, side AC and the perpendicular bisector of BC meet in point D, and BD bisects ∠ABC。 If AD = 9 and DC = 7, what is the area of triangle ABD?

Learn more about the Area of the triangle at

brainly.com/question/23945265

#SPJ4

6 0

2 years ago