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
Dafna11 [192]
3 years ago
12

A circular pool of radius r m has a path 2 m wide around its perimeter. If the area of the pool is four-fifths of the total area

, prove that r²-16r-16=0. Hence calculate the radius of the pool in metres.
Mathematics
1 answer:
Rainbow [258]3 years ago
4 0

9514 1404 393

Answer:

  pool radius is 8+4√5 ≈ 16.94 meters

Step-by-step explanation:

Let r represent the radius of the pool. Then r+2 is the radius to the outside of the walkway. The ratio of areas is given as 4/5, so we have ...

  πr²/(π(r+2)²) = 4/5

  5r² = 4(r² +4r +4) . . . . cross-multiply

  r² -16r -16 = 0 . . . . . . . subtract the right-side expression from both sides

__

  r² -16r +64 = 80 . . . . . add 80 to complete the square

  (r -8)² = 80

  r -8 = √80 = 4√5 . . . . square root; use only the positive root

  r = 8 +4√5 ≈ 16.94 . . . meters

The radius of the pool is 8+4√5 ≈ 16.94 meters.

_____

The area of a circle of radius r is given by the formula ...

  A = πr²

You might be interested in
Giving 30 points pls answer correctly
Mademuasel [1]

Answer:

B. 20.41

Step-by-step explanation:

I hope this helps! pls brainliest:D

5 0
2 years ago
2.–/1 pointsMy Notes
Hitman42 [59]
What is "b" ???????????
6 0
3 years ago
An employee was randomly chosen from a company. If the expected value of the age of the employee is _____ years old, the mean ag
Vinil7 [7]
This employee who was randomly chosen represents the population of the company. This means that, any parameter measured through this employee can be considered as the mean or average value for the whole population (the company).

Based on this, taking the age of the employee as the desired parameter, the age of this employee will be considered as the average or mean age for the whole company. This means that the age of the employee and the mean age of all employees are equal.

Therefore, the answer is C) 32, 32
<span>An employee was randomly chosen from a company. If the expected value of the age of the employee is 32 years old, the mean age of all the employees in the company is 32 years old.</span>
5 0
3 years ago
Read 2 more answers
Please help with calculations!
ASHA 777 [7]

Resumen de primeros 4 años en Medicina (bioquimica, geneticas, salud publica, ética, etc)

Save Med Esencial Ciencias Básicas - Inglés- For Later

Save

Embed

Share

Print

RELATED TITLES

Carousel Next


6 0
3 years ago
Which of the following choices
Lapatulllka [165]

Answer:

Denote AH as height of triangle ABC, with H lies on BC.

Applying sine theorem:

AH/AC = sin 60

=> AH = AC x sin 60 = 47 x sqrt(3)/2 = 40.7

=> Area of triangle ABC is calculated by:

A = AH x BC x (1/2) = 40.7 x 30 x (1/2) = 610.5 = ~611

=> Option C is correct.

Hope this helps!

:)

3 0
3 years ago
Other questions:
  • Plz help me.<br><br> I don't know how to do this!!!
    13·1 answer
  • X^+5x+8=0<br> What is the answer to this question
    15·1 answer
  • Use the relationship between the since and cosine functions to fill in each blank.
    10·1 answer
  • Could someone please help?
    9·2 answers
  • Walter slater sells appliances and earns 2.5 percent commission in addition to his salary. last month he sold $63,000 in applian
    11·2 answers
  • (giving brainiest)
    13·1 answer
  • Please help Omg please please please I’m praying somebody helps
    8·1 answer
  • The store's rectangular floor is 42 meters long and 39 meters wide. How many meters of flooring do they need? Use estimation to
    6·1 answer
  • I will put a answer up in 3 hours i have 30,000 points so be ready
    6·2 answers
  • -11-(-5)
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!