1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
34kurt
2 years ago
5

If a circle has a diameter of 11.5 feet, what is the area?

Mathematics
1 answer:
OverLord2011 [107]2 years ago
3 0

Answer:

103.87 ft.

In this case, area equals \pi r^2

The diameter is 2r

But before worrying about anything else, we must start the problem. Let's do that now.

The first step is to find the broken-down form of the area.

A = \frac{1}{4} \pi d^2

Next, break this equation into a solvable definition.

\frac{1}{4} * \pi  * 11.5

Lastly, solve this equation, and round.

A ≈ 103.86891~ft^2

You might be interested in
Among persons donating blood to a clinic, 85% have Rh+ blood (that is, the Rhesus factor is present in their blood.) Six people
Leona [35]

Answer:

a) There is a 62.29% probability that at least one of the five does not have the Rh factor.

b) There is a 22.36% probability that at most four of the six have Rh+ blood.

c) There need to be at least 8 people to have the probability of obtaining blood from at least six Rh+ donors over 0.95.

Step-by-step explanation:

For each person donating blood, there are only two possible outcomes. Either they have Rh+ blood, or they do not. This means that we use the binomial probability distribution to solve this problem.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

In which C_{n,x} is the number of different combinatios of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

And p is the probability of X happening.

In this problem we have that:

p = 0.85, n = 6.

a) fine the probability that at least one of the five does not have the Rh factor.

Either all six have the factor, or at least one of them do not. The sum of the probabilities of these events is decimal 1. So:

P(X < 6) + P(X = 6) = 1

P(X < 6) = 1 - P(X = 6)

In which:

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 6) = C_{6,6}.(0.85)^{6}.(0.15)^{0} = 0.3771

So

P(X < 6) = 1 - P(X = 6) = 1 - 0.3771 = 0.6229

There is a 62.29% probability that at least one of the five does not have the Rh factor.

b) find the probability that at most four of the six have Rh+ blood.

Either more than four have Rh+ blood, or at most four have. So

P(X \leq 4) + P(X > 4) = 1

P(X \leq 4) = 1 - P(X > 4)

In which

P(X > 4) = P(X = 5) + P(X = 6)

P(X = 5) = C_{6,5}.(0.85)^{5}.(0.15)^{1} = 0.3993

P(X = 6) = C_{6,6}.(0.85)^{6}.(0.15)^{0} = 0.3771

P(X > 4) = P(X = 5) + P(X = 6) = 0.3993 + 0.3771 = 0.7764

P(X \leq 4) = 1 - P(X > 4) = 1 - 0.7764 = 0.2236

There is a 22.36% probability that at most four of the six have Rh+ blood.

c) The clinic needs six Rh+ donors on a certain day. How many people must donate blood to have the probability of obtaining blood from at least six Rh+ donors over 0.95?

With 6 donors:

P(X = 6) = C_{6,6}.(0.85)^{6}.(0.15)^{0} = 0.3771

37.71% probability of obtaining blood from at least six Rh+ donors over 0.95.

With 7 donors:

P(X = 6) = C_{7,6}.(0.85)^{6}.(0.15)^{1} = 0.3960

0.3771 + 0.3960 = 0.7764 = 77.64% probability of obtaining blood from at least six Rh+ donors over 0.95.

With 8 donors

P(X = 6) = C_{8,6}.(0.85)^{6}.(0.15)^{2} = 0.2376

0.3771 + 0.3960 + 0.2376 = 1.01 = 101% probability of obtaining blood from at least six Rh+ donors over 0.95.

There need to be at least 8 people to have the probability of obtaining blood from at least six Rh+ donors over 0.95.

5 0
3 years ago
If each member of a family of four were to drink the entire contents of a 6 fluid ounce juice box each dsy during lunch, what wo
adelina 88 [10]

Answer:

84

Step-by-step explanation:

6 times 7 is 42

42 times 2 is 84

5 0
3 years ago
Please help urgent fasttt
sergeinik [125]

Answer:

  • Perimeter= l1+l2+w3+w4
  • Where l1 and l2 are equal in magnitude
  • Alike w3 and l
  • w4 are equal in magnitude
  • l= (2×w)+8
  • Plug it in to the equation

3 0
2 years ago
Graph these equations:<br> x + 3y = 6<br> x + 3y = 9
Evgen [1.6K]
I don’t know if you can see this but I hope it does if u don’t understand let me know so I can explain!

6 0
3 years ago
Can you help me with this question i dont get it
Marizza181 [45]
The answer is c or A
3 0
3 years ago
Read 2 more answers
Other questions:
  • Add [1 -4 3 5]+[-2 6 -2 4]​
    5·2 answers
  • If sin theta = 5/6, what are the values of cos theta and tan theta?
    14·1 answer
  • The specification for the pull strength of a wire that connects an integrated circuit to its frame is 10 g or more. In a sample
    9·1 answer
  • Jonathan bought a table and some chairs at a furniture store. The equation that models this situation is y=25x+80, where y is th
    5·2 answers
  • Helppppppppppp please!!!
    15·1 answer
  • Find two possible factors for the estimated product 1600
    11·1 answer
  • I just stuck. Someone explain.
    5·1 answer
  • Write 5.9 as a mixed number.
    11·2 answers
  • Identify the number that does not belong with the other three. Explain your reasoning.
    9·2 answers
  • What is the ratio of cups pretzles to cups of almonds?
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!