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
I need help with this question please
Stella [2.4K]

Answer:

There are all true statements

Step-by-step explanation:

the graph is just trying to confuse you but it's simple just find the letters on the graph then see if they look how the show it below

6 0
2 years ago
Consider a political discussion group consisting of 4 ​Democrats, 4 ​Republicans, and 5 Independents. Suppose that two group mem
kumpel [21]

steps:
total: 13 ppl
republicans: 4
1st person: 13-4/13 9/13
2nd person: 12-4/12 (because one person was taken out). 8/12
6 0
2 years ago
Shelby Middle School is thinking of changing its dress code. What would be the best way to collect data?
mixas84 [53]

Answer:

Choose every tenth student entering the school and ask them if they like the dress code or not.

Step-by-step explanation:

This is a question of sampling. We need to make non-biased predictions using non-biased data. We can sample from every tenth student to stay proportional. Sampling many students can collect more data and can help keep the data non-biased.

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

8 0
2 years ago
3(x + 4) = 27 what is x
Alla [95]

Answer:

x = 5

Step-by-step explanation:

This is a simple equation if you look at it right and don't get scared by the "x."

All we need to do is figure out what times 3 = 27. We can do this easily by diving 27 by 3.

27 ÷ 3 = 9

Since our "equation" is 3(x + 4) = 27 we know whatever is in the parenthesis () has to equal to 9. We already get 4 so:

5 + 4 = 9.

3 times 9 = 27.

5 is your answer.

<u>Hope this helps and have a nice day!</u>

PS if you could mark brainliest that'd be great! I'm very close the "expert" rank. Haha, sorry I usually don't ask.

6 0
2 years ago
A ladder leaning against a wall makes an angle of 45º with the ground. If the length of the ladder is 20 feet, find the approxim
Sveta_85 [38]

Answer:The way to answer this would be to show you a calculator's answer

Step-by-step explanation:

https://www.calculator.net/triangle-calculator.html?vc=45&vx=&vy=20&va=90&vz=&vb=45&angleunits=d&x=62&y=20

6 0
3 years ago
Other questions:
  • Calvin deposited $12,600 into a savings account, and he didn't make any deposits or withdrawals for a year. If, after interest w
    13·1 answer
  • Please guysss help me with this question!!!!!
    13·1 answer
  • For which of the following graphs would it NOT make sense to connect
    15·1 answer
  • 10^2+12^2+14^2+......+26^2=??
    9·1 answer
  • it is 35 degrees Celsius at your school and 90 degrees farenheit at home. where is the tempature higher?​
    5·2 answers
  • If the lengths of the legs of a right triangle are 5 and 12, what is the length of the hypotenuse?
    7·1 answer
  • The matrix below represents a system of equations. (Image) What is the solution to this system of equations
    15·1 answer
  • The length of a rectangle is 4 meters less than twice it's width. the area of the rectangle 70 find the dimensions of the rectan
    5·1 answer
  • shows that the points (2,1), (6,2), (5,6), and (1,5) are the vertices of a square. Then obtain the perimeter and area of ​​that
    12·1 answer
  • Helpppppppppppppppppppppppppppppppppppppppppppppppppppppp
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!