Answer:
D. 221.7 cm
Step-by-step explanation:
Surface area of a sphere is: [tex]SA=4\pi r^2[/tex]
'r' - radius
We are given the radius of 4.2 centimetres.
[tex]SA=4\pi 4.2^2\\4 * \pi * 4.2^2\\\rightarrow 4.2^2 =17.64\\\text {Using 3.14 for pi: }\\4 * 3.14 *17.64\\12.56*17.64\\\boxed {221.5584}[/tex]
221.5584 ≈ 221.6
The closest answer is Option D, therefore it should be the correct answer.
To measure the height of the cloud cover at an airport, a worker shines a spotlight upward at an angle 75° from the horizontal. an observer at a distance d = 560 m away measures the angle of elevation to the spot of light to be 45°. find the height h of the cloud cover,
Answer:
The height of the cloud cover is 441.66 meters
Step-by-step explanation:
Distance = 560 m
The height of the cloud cover = h meters
According to the diagram, the worker stands at point R,
Let RT = x
tan 45⁰ = [tex]\frac{opposite}{adjacent}[/tex] = [tex]\frac{h}{x}[/tex]
therefore, 1 = [tex]\frac{h}{x}[/tex], h = x
Then tan 75⁰ = [tex]\frac{h}{560-x}[/tex], substituting x = h, we have
3.732 = [tex]\frac{h}{560-h}[/tex]
3.732(560 - h) = h
3.732 × 560 = 3.732h + h
2089.92 = 4.732h
h = 441.66 m
The height of the cloud cover is 228.62 meters
The given parameters are:
[tex]\mathbf{\alpha = 75^o}[/tex]
[tex]\mathbf{\theta = 45^o}[/tex]
[tex]\mathbf{d = 560m}[/tex]
See attachment for the image of the cloud cover.
From the attached image, we have the following sine ratios:
[tex]\mathbf{sin(75) = \frac hx}[/tex]
[tex]\mathbf{sin(45) = \frac h{560 - x}}[/tex]
Make h the subject in both equations
[tex]\mathbf{ h = xsin(75)}[/tex]
[tex]\mathbf{ h = (560 - x) sin(45)}[/tex]
So, we have:
[tex]\mathbf{ xsin(75) = (560 - x) sin(45)}[/tex]
Open brackets
[tex]\mathbf{ xsin(75) = 560sin(45) - x sin(45)}[/tex]
Collect like terms
[tex]\mathbf{ xsin(75) + x sin(45)= 560sin(45) }[/tex]
Evaluate sine 45 and 75
[tex]\mathbf{ 0.9659x + 0.7071x= 560 \times 0.7071}[/tex]
[tex]\mathbf{ 1.673x= 395.976}[/tex]
Divide both sides by 1.673
[tex]\mathbf{ x= 236.69}[/tex]
Recall that:
[tex]\mathbf{ h = xsin(75)}[/tex]
So, we have:
[tex]\mathbf{h = 236.69 \times 0.9659}[/tex]
[tex]\mathbf{h = 228.618871}[/tex]
Approximate
[tex]\mathbf{h = 228.62}[/tex]
Hence, the height of the cloud cover is 228.62 meters
Read more at:
https://brainly.com/question/16979479
The sum of the measures of the angles of a triangle is 180. The sum of the measures of the second and third angles is five times the measure of the first angle. The third angle is 14 more than the second. Let x, y, and z represent the measures of the first, second, and third angles, respectively. Find the measures of the three angles.
Answer:
[tex]x=30\\y=68\\z=82[/tex]
Step-by-step explanation:
x = measure of the first angle
y = measure of the second angle
z = measure of the third angle
The sum of the measures of the second and third (y+z) is five times the measure of the first angle (=5x)
[tex]y+z=5x[/tex]
The third angle is 14 more than the second
[tex]z=y+14[/tex]
And remember that the sum of these three angles must be equal to 180.
[tex]x+y+z=180[/tex]
Let's take these equations
[tex]y+z=5x\\z=y+14\\x+y+z=180[/tex]
If you take a look at the first equation, we have y+z = 5x and we have y+z in the third equation as well, we can replace that....
[tex]x+y+z=180\\x+(y+z)=180\\x+(5x)=180[/tex]
Distribute the + sign
[tex]x+5x=180[/tex]
Combine like terms;
[tex]6x=180[/tex]
Divide by 6.
[tex]x=\frac{180}{6}\\ x=30[/tex]
We have now defined that the measure of the first angle is 30º.
Let's take another equation... for example [tex]z=y+14[/tex]
I'm going to take this one because if I replace x and z in the third equation, all I'll have left will be y.
[tex]x+y+z=180\\30+y+(y+14)=180[/tex]
Distribute the + sign and Combine like terms;
[tex]30+y+y+14=180\\44+2y=180\\[/tex]
Subtract 44 to isolate 2y.
[tex]2y=180-44\\2y=136[/tex]
Now divide by 2.
[tex]y=\frac{136}{2}\\ y=68[/tex]
We already have the value of x and y. Once again, replacing this in the third equation will leave us with z to solve for.
[tex]x+y+z=180\\30+68+z=180\\98+z=180\\z=180-98\\z=82[/tex]
c. two hundred thirty-one and five tenths - in decimal standard form
Answer:
231.5
five tenths = 0.5
Ginger still has 40 percent of her book to read. If she has read 180 pages, how many pages does she still have to read?
Answer:
Ginger still has 40 percent of her book to read. If she has read 180 pages, the number of pages she still have to read:
N = 180 x (100 - 40)/40 = 270 pages
Hope this helps!
:)
How many boys are there in an introductory geology course if 360 students are enrolled and there are five boys to every seven girls?
Answer:150 branliest
Step-by-step explanation:
Answer:
150
Step-by-step explanation:
360/(5+7)=30
30*5=150
Carpetland carpet installers incur an average cost of $300 for each carpet installed. Joan Chin, the firm’s vice president, proposes a new procedure for installations, which she hopes will be more efficient. Joan plans to run a trial and hopes that the results of a trial period will enable her to conclude with a level of significance of 0.05 that the new procedure reduces the average cost to install a carpet. If Joan's hypothesis test results in a Type II error, what would this mean?
Answer:
A Type II error happens when the null hypothesis failed to be rejected, although it is false and the alternative hypothesis is true.
In this context, would be that the test does not give enough evidence to support the claim that the new procedure reduces the average cost, although it really does reduces it.
The new procedure is effective, but the sample does not give enough evidence.
Step-by-step explanation:
You need to be taller than 48" to ride the roller coaster. Which of the following inequalities shows the height Susan has to be to ride the roller coaster.
h < 48"
h > 48"
h ≤ 48"
h ≥ 48"
Answer:
> 48"
Step-by-step explanation:
> represents greater than 48"
A bag contains 10 Yellow, 4 Green and 7 Blue marbles. Find the following probabilies.
P(blue)
Answer:
1/3
Step-by-step explanation:
The total number of marbles
10+4+7 = 21
P(blue) = blue marbles / total marbles
= 7 / 21
= 1/3
Find the greatest common factor of the
following monomials:
34c3 2c5
Answer:2c^2
Step-by-step explanation:
34c^3 and 2c^5
34c^3=2 x 16 x c x c^2
2c^5=2 x c^2 x c^3
Greatest common factor =2 x c^2
Greatest common factor =2c^2
Please help ASAP! I will mark Brainliest! Please READ the question THEN answer CORRECTLY! No guessing!
Answer:
C. [tex]\frac{\sqrt{5} }{8}[/tex]
Step-by-step explanation:
This expression can be rewritten as [tex]\frac{\sqrt{5} }{\sqrt{64} }[/tex].
Since the square root of 5 is prime and does not have any perfect square factors, it cannot be simplified. However, the square root of 64 is equal to 8, so our final simplified radical expression would be [tex]\frac{\sqrt{5} }{8}[/tex], which is option C.
HOPE THIS HELPED! :)
Answer:
C is the answer
Step-by-step explanation:
You have to rewrite as [tex]\sqrt{5}[/tex]/[tex]\sqrt{64}[/tex]. Then you have to simplify the denominator which is 8. That is how you get your answer.
Hope this helps.
Find the surface area of the pyramid to the nearest whole number.
Answer:
i think its 248m^2
Step-by-step explanation:
Solve each equation.
13 = -2w
Answer:
w = -6.5
Step-by-step explanation:
We want to get rid of the coefficient of w so that we can solve for w. To do that, let's divide both sides of the equation by -2. When we do so, we get -13/2 = w. Hope this helps!
Ms Davis is doing an activity with her statistic students where she gives them a 20 question multiple top choice test and they know none of the answers. Students need to guess on every question and each question has 5 possible choices, 1 of the which is correct.
What is the mean and standard deviation of the number of questions that each student gets correct?
Answer:
The mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.
Step-by-step explanation:
Let the random variable X be defined as the number of correct answers marked by a student.
It is provided that each question has 5 possible choices, 1 of the which is correct.
Then the probability of marking thee correct option is:
[tex]P(X)=\frac{1}{5}=0.20[/tex]
There are a total of n = 20 questions to be answered.
As the students does not the answer to any question, they would be guessing for each question. This implies that for a random question, all the five options has the equal probability of being correct and each of the five options can be correct independently from the other.
All these information above indicates that the random variable X follows a Binomial distribution with parameters n = 20 and p = 0.20.
The mean and standard deviation of a Binomial distribution are:
[tex]\mu=np\\\\\sigma=\sqrt{np(1-p)}[/tex]
Compute the mean and standard deviation of the random variable X as follows:
[tex]\mu=np=20\times 0.20=4\\\\\sigma=\sqrt{np(1-p)}=\sqrt{20\times 0.20\times(1-0.20)}=1.789[/tex]
Thus, the mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.
According to the question,
The probability of making 3 correct options will be:
→ [tex]P(X) = \frac{1}{5}[/tex]
[tex]= 0.20[/tex]
Total number of questions,
n = 20As we know,
The mean will be:
→ [tex]\mu = np[/tex]
By substituting the values, we get
[tex]= 20\times 0.20[/tex]
[tex]= 4[/tex]
and,
The standard deviation will be:
→ [tex]\sigma = \sqrt{np(1-p)}[/tex]
[tex]= \sqrt{20\times 0.20\times (1-0.20)}[/tex]
[tex]= 1.789[/tex]
Thus the responses above are correct.
Learn more about standard deviation here:
https://brainly.com/question/20896613
The corresponding sides of ΔABC and ΔDEF have equal lengths. The area of ΔABC is 4 square units, and the longest side of ΔDEF is 5 units long. What is the area of ΔDEF?
Answer:
4 square units
Step-by-step explanation:
If corresponding sides have equal lengths, the triangles are congruent by the SSS postulate. They must have equal areas: 4 square units.
ΔDEF has an area of 4 square units.
Answer:
if the corresponding sides are equal the 2 triangles are congruent ( by SSS) so their areas are the same.
So area of triangle DEF = 4 sq units
Step-by-step explanation:
add 5 1/2 kg to 450g
1kg = 1000g
51/2 kg= 51/2×1000=51×500=25500g
25500g+450g= 25950g
Answer:
[tex]5950g[/tex]
Step-by-step explanation:
[tex]5 \frac{1}{2} kg \\ = 5kg \: 500g \\ = 5500g[/tex]
Now let's add.[tex] \: \: \: \: \: \: 5500g \\ + \: \: \: \: 450g \\ =5950 g[/tex]
So the correct answer is,[tex] = 5950g = 5kg \: 950g[/tex]
hope this helps
brainliest appreciated
good luck! have a nice day!
What is the solution to the system of equations?
3 x + 10 y = negative 47. 5 x minus 7 y = 40.
(1, –5)
(1, 5)
(–1, –5)
(–1, 5)
Answer:
(1, –5)
Step-by-step explanation:
It is relatively easy to try the offered solutions to see what works.
(1, -5)
3(1) +10(-5) = -47 . . . true
5(1) -7(-5) = 40 . . . true
(1, -5) is the solution
_____
As a check, you can try some of the other choices:
(1, 5)
3(1) +10(5) ≠ -47
(-1, -5)
3(-1) +10(-5) ≠ -47
(-1, 5)
3(-1) +10(5) ≠ -47
None of the other choices works in the first equation, so they're not the solution.
Answer:
(1,-5)
Step-by-step explanation:
1)get desmos
2)put in numbers
3)where they intersect is the answer.
easy as pie... oh wait pie ain't easy...
easy as ramen
White and black shapes are used in a game Some of the shapes are circles All the other shapes are squares The ratio of white to black shapes is 5:11 The ration of white circles to white squares is 3:7 The ratio of black circles to black squares is 3:8 What fraction of all the shapes are circles
Answer:
9/32
hope this helps
If f(x)=9x+2, What is the value of the function when x=4?
If f(x)=9x+2, for what value of x is the value of the function 29?
Answer:
1) 38
2) 3
Step-by-step explanation:
f(x)=36+2
f(x)=38
29=9x+2
27=9x
x=3
Question: What is the value of the function at x=−2?
Answer: y=2
Step-by-step explanation: I took the test.
*THIS IS THE CORRECT ANSWER. PLEASE DON'T ANSWER 3. IT IS WRONG!*
55 POINTS IF YOU GET RIGHT THEN GOATED AND BRAINIEST!!
Answer:
17 i would say it is D
18 i belive it is B
19 it is c
20 A
Gibbs Baby Food Company wishes to compare the weight gain of infants using its brand versus its competitor’s. A sample of 40 babies using the Gibbs products revealed a mean weight gain of 7.6 pounds in the first three months after birth. For the Gibbs brand, the population standard deviation of the sample is 2.3 pounds. A sample of 55 babies using the competitor’s brand revealed a mean increase in weight of 8.1 pounds. The population standard deviation is 2.9 pounds. At the .05 significance level, can we con- clude that babies using the Gibbs brand gained less weight? Compute the p-value and interpret it.
Answer:
[tex]z=\frac{(7.6-8.1)-0}{\sqrt{\frac{2.3^2}{40}+\frac{2.9^2}{55}}}}=-0.936[/tex]
The p value can be founded with this formula:
[tex]p_v =P(z<-0.936)=0.175[/tex]
Since the p value is higher than the significance level provided of 0.05 we have enough evidence to FAIL to reject the null hypothesis and we can't conclude that the true mean for the Gibbs brand is significantly lower than the true mean for the competitor
Step-by-step explanation:
Information given
[tex]\bar X_{1}=7.6[/tex] represent the mean for Gibbs products
[tex]\bar X_{2}=8.1[/tex] represent the mean for the competitor
[tex]\sigma_{1}=2.3[/tex] represent the population standard deviation for Gibbs
[tex]\sigma_{2}=2.9[/tex] represent the sample standard deviation for the competitor
[tex]n_{1}=40[/tex] sample size for the group Gibbs
[tex]n_{2}=55[/tex] sample size for the group competitor
[tex]\alpha=0.05[/tex] Significance level provided
z would represent the statistic
Hypothesis to verify
We want to check if babies using the Gibbs brand gained less weight, the system of hypothesis would be:
Null hypothesis:[tex]\mu_{1}-\mu_{2}=0[/tex]
Alternative hypothesis:[tex]\mu_{1} - \mu_{2}< 0[/tex]
The statistic would be given by:
[tex]z=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}[/tex] (1)
Replacing the info given we got:
[tex]z=\frac{(7.6-8.1)-0}{\sqrt{\frac{2.3^2}{40}+\frac{2.9^2}{55}}}}=-0.936[/tex]
The p value can be founded with this formula:
[tex]p_v =P(z<-0.936)=0.175[/tex]
Since the p value is higher than the significance level provided of 0.05 we have enough evidence to FAIL to reject the null hypothesis and we can't conclude that the true mean for the Gibbs brand is significantly lower than the true mean for the competitor
Please help ASAP! I will mark Brainliest! Please answer CORRECTLY! No guessing!
Answer:
Option D: 5591.93
Step-by-step explanation:
The best way to understand this question is to apply the formula in an indirect manner;
P - Principle number, Starting Value
T - Time
I - Interest
Let us convert the interest into decimal form, such that 3.8% is shifted two decimal points to the right ⇒ 0.038. Now add 1 to this value to get ⇒ 1.038. By PEDMAS, you would first raise this value to the span of 3 years as such:
(1.038)^3 = 1.118386872.......
The final step would by to multiply the starting value (investment $) $ 5,000 by this continuing value of 1.118386872:
5,000(1.118386872) = 5591.93436 ⇒ Rounded to (About) 5591.93
Answer:D
Step-by-step explanation:
principal=p=$5000
Rate=r=3.8%
Time=n=3 years
amount=a
a=p(1+r/100)^n
a=5000(1+3.8/100)^3
a=5000(1+0.038)^3
a=5000(1.038)^3
a=5000 x 1.038 x 1.038 x 1.038
a=5591.93
a=$5591.93
Subtracting by adding up 65-39
Answer:
26Step-by-step explanation:
In order to subtract by adding up 65-39, we need to add -39 to the value of 65. This can be rewritten in this way;
65+(-39)
The equation above is similar to the one given because the product of a minus and a plus sign will still give us back a minus sign.
on solving;
65+(-39) = 26
2. Inflation is at a rate of 7% per year. Evan's favorite bread now costs $1.79. What did it cost 10 years ago? How long
before the cost of the bread doubles?
Answer:
It cost $0.91 10 years ago.
It takes 10.24 years for the cost of bread to double.
Step-by-step explanation:
The equation for the price of bread after t years has the following format:
[tex]P(t) = P(0)(1+r)^{t}[/tex]
In which P(0) is the current price, and r is the inflation rate, as a decimal.
If we want to find the price for example, 10 years ago, we find P(-10).
Inflation is at a rate of 7% per year. Evan's favorite bread now costs $1.79.
This means that [tex]r = 0.07, P(0) = 1.79[/tex]. So
[tex]P(t) = P(0)(1+r)^{t}[/tex]
[tex]P(t) = 1.79(1+0.07)^{t}[/tex]
[tex]P(t) = 1.79(1.07)^{t}[/tex]
What did it cost 10 years ago?
[tex]P(-10) = 1.79(1.07)^{-10} = 0.91[/tex]
It cost $0.91 10 years ago.
How long before the cost of the bread doubles?
This is t for which P(t) = 2P(0) = 2*1.79. So
[tex]P(t) = 1.79(1.07)^{t}[/tex]
[tex]2*1.79 = 1.79(1.07)^{t}[/tex]
[tex](1.07)^{t} = 2[/tex]
[tex]\log{(1.07)^{t}} = \log{2}[/tex]
[tex]t\log{1.07} = \log{2}[/tex]
[tex]t = \frac{\log{2}}{\log{1.07}}[/tex]
[tex]t = 10.24[/tex]
It takes 10.24 years for the cost of bread to double.
Simplify the radical below.
Square root 84
A. 221
B. 242
C. 4.21
D. 4.42
Pls no explanation will give you 20 points in in a hurry
the answer is B
Step-by-step explanation:
and I would love 20 points
A ball is thrown straight up from a cliff. The function f(x)= -4.9t^ + 17t +19 describes the height of the ball, in meters, as a function of time, t, in seconds. What is the maximum height of the ball? At what time is the height reached? Round your answer to one decimal place.
Answer:
33.7 m at 1.7 seconds
Step-by-step explanation:
For quadratic ax^2+bx+c, the line of symmetry (x-coordinate of the vertex) is ...
-b/(2a)
For your quadratic, the vertex (highest point) is reached at time ...
t = -(17)/(2(-4.9)) = 17/9.8 ≈ 1.7 . . . . seconds
__
The height at that time is ...
f(17/9.8) = (-4.9(17/9.8) +17)(17/9.8) +19 = 289/19.6 +19 ≈ 33.7 . . . meters
_____
Comment on the function evaluation
We have used the "Horner form" of the function to make evaluation easier.
f(t) = (-4.9t +17)t +19
Really need help on this. I keep gettin it wrong please help!!!
Answer:
1436.76 m³
Step-by-step explanation:
Volume of sphere= 4/3 π r ³
V= 4/3(3.14)(7)³
V=4/3(3.14)(343)
V= 4310.26 / 3
V= 1436.76 m³
the midpoint of AB is point P at (-16,6) if point A is at (-10,8) what are the coordinates of point B?
Answer:
Denote B(x, y), we have:
-10 + x = 2 x (-16) => x = -22
8 + y = 2 x 6 => y = 4
=> B(-22, 4)
Hope this helps!
:)
Rewrite the percentage in the sentence below as a decimal.
The 20 overseas investors own 7.2% of the business.
Answer:
0.072
Step-by-step explanation:
Answer:0.072
Step-by-step explanation:
7.2% = 7.2/100
7.2 ➗ 100=0.072
simplify the expression (3k / 8)^2
Answer:
9k/64^2 (9k^2/64^2)
Step-by-step explanation:
Answer:
9k^2/64
Step-by-step explanation:
3*3=9
k*k=k^2
8*8=64
If you roll a die three times, what is the probability of rolling three ONES?
(Give your answer as a decimal, rounded to the nearest thousandth. That is, rounded to three decimal places.)
Answer:
0.004
Step-by-step explanation:
The probability of rolling any number is 1/6 so that times 3 is 1/216 that as a decimal i 0.004
