M4maths Previous Puzzles

05 Jul 2016 Radius of fountain

A park is in the form of a rectangle. At the centre of the park there is a circular fountain. The area of the park excluding the fountain is 2086 m^2. The dimension of the park are 70m*65m. Find the radius of the fountain.

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OPtion

1) 24 m
2) 7 m
3) 14 m
4) 18 m
5) 22 m
6) 26 m
7) 36 m
8) 39 m
9) 28 m
10) None of these

Solution

area of circular fountain = area of rectangle - remaining area
= 70*65 - 2086 m^2
4550 - 2086 = 2465 m^2
=> 22/7 r^2 = 2464
=> r^2 = 784 m^2
=> r = 28 m
Option 9)

Correct Option: 9 Best Solution (33)

swarupa malakala   8 years AGO

Area of park=70*65=4550m2
The area of park excluding fountain = area of park- area of fountain
2086=4550-πr2
r=√(4550-2086)/π
r=28

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Jaspalsingh Parmar   8 years AGO

Area of rectangle = 70*65 = 4550
Area of fountain = 4550 - 2086 = 2464
So (22/7)* R^2 = 2464

So R = 28 m

Like? Yes (1) | No   

Vipul Puranik   8 years AGO

Total area of park = 70*65 = 4550 m^2
Area excluding fountain = 2086 m^2
Hence, remaining area of fountain = 4550 - 2086 = 2464 m^2
22/7*r*r = 2464 m^2
r*r = 784 m^2
r = 28m

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SURAJ PANDEY   8 years AGO

area of rectangle - area of fountain = 2086
70*65 - area of fountain = 2086
solving we get
area of fountain = 2464
as fountain is of circular area we can find its radius by formula
radius = 28m

Like? Yes (1) | No   

kavya   8 years AGO

area except fountain = 2080m^2
area of rectangle=70*65m^2
area of fountain=area of rectangle-area except fountain
AF=4550-2080
AF=2470
pi r^2=2470
r=sqrt(2470/3.14)
AF=28.6m

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b sarath chandra   8 years AGO

PI*r*r+2086=70*65
PI*r*r=4550-2086
PI*r*r=2464
r*r=2464/PI
[PI=22/7]
r= sqrt(784)
r=28m

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Param   8 years AGO

Area of park=70*65=4550
Area of fountain = 4550-2086 = 2464

As fountain is circular,
Area of fountain = pi*r*r = 2464

r*r = 784

r = 28m

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sanjeet kumar   8 years AGO

70*65 - pi * r ^2 = 2086
On solving we get,
r = 28 m

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anugna mythri   8 years AGO

Area of rectangle is 70*65.= 4550m^2 and given radius 2086 m^2 so deduct 2086 from 4550.to get area of circle it is 2464 finding r from pi*r^2= 2464 we get r=28

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Ankit   8 years AGO

Total area of the rectangle is = 4550 m^2
Area of circular fountain is = (area of rectangle - area of remaining area)
4550-2086 = 2464

now, pi x r^2 = 2464
r = 28m

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Vijayalakshmi Kandhan   8 years AGO

A park is rectangular which area is 70m*65m=4550(m^2). and the area of park excluding fountain is 2086 m^2. hence the area of circular fountain is 4550-2086=2464 m^2. area of circle is 22/7*r*r=2464m^2. r^2= 2464*7/22. radius r=28m.

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A.KARTHIKA   8 years AGO

Area of the rectangle park is,
=70*65=4550
Area of the rectangle park excluding foundation,
=2086 m^2
diff between areas= 4550-2086 = 2464
Area=22/7*r^2
r^2= area*7/22
r^2=2464*7/22 = 784
r^2=784
r=28 m
ANS:28 m

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Srikanthreddy    8 years AGO

=>total area of rectangle=70*65 = 4550 m^2.
=>So,area of circular fountain=> 4550-2086 = 2464 m^2.
=>Radius of fountain=>Pi*r^2 = 2464
=>r^2 = (2464*7)/22=784
=>r(radius) = 28 m.

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Pranay   8 years AGO

area of the rectanglular park - area of park excluding mountain gives circular fountain area. then using circle area formula we can find radius.

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Namrta shahapurkar   8 years AGO

Area of park-4550
Area of fountai-2464

Area of circle=22/7*r*r
r=28

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Hemant Kanyal   8 years AGO

Area of rectange - area of circle = 2086
Area of rectangle = 4550
So, radius^2 = 7*2464/22
So, radius = 28

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sweety agarwal   8 years AGO

the total area of the park is =70*65=4550
and the area excluding fountain is 2086
so the area of the fountain circle is 4550 - 2086 =2464
2464= PI r^2
r=28

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Jayanth.V   8 years AGO

area of fountain =area of rectangle - area excluding fountain
so= 4550-2086
than solve for,area of circle..
so r=28m

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kiran   8 years AGO

rectangle area - circle excluded rectangle = circle area

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Raushan   8 years AGO

becoz we can find rectangle area by using dimension,and then subtract to given area to calculate fountain area and then area=22/7*r*r
simple r=28 m

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Surendra Naraga   8 years AGO

Actual area of the park= 70*65 = 4550m^2
Area of the park excluding fountain=2086m^2
Area of the circular fountain = 4550-2086=2464 m^2
Area of the circle= pi.r^2
r^2=2464/pi
r^2=784.32
r=sqrt(784.32)
r=28.00
So the radius of the fountain is 28m.

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bharath   8 years AGO

28m
70*65=4550
4550-2086=2464
r2=2464/3.141
r=28.00

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nadeem zaya   8 years AGO

area of fountain is equal to the difference of area of whole reactangle park and area of park excluding fountain

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sahil   8 years AGO

total area of rectangular -area of park excluding circle= area of circle

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Gokul Krishnan   8 years AGO

tot area=350+2086=2436
22/7*R^2=2436
R=28

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Mrs.Thangaraj   8 years AGO

null

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balaji ram   8 years AGO

the whole are of the park is found from the dimension and it is subtracted with area excluding fountain. frm we got the area of fountain and using the pi/4* d^2 equals area we get the answer

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Shruti Mathur   8 years AGO

given area is of rectangle fountain area is not included.
Take the total of rectangle minus area of fountain is equal to 2086 m*2

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Akshat Sood   8 years AGO

Area of park excluding fountain=2086m^2

Area of park=60*75=4550m^2

Area of fountain=4550-2086=2464m^2

Now pi*r^2=2464

r=28 m [option 9]

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Jaikumar Bhatia   8 years AGO

Area of Park=70*65=4550m^2.........................(a)
Area of Park excluding fountain=2086m^2.....(b)
Area of Fountain=(a)-(b)=4550-2086=2464m^2
(Pi/4)d^2=2464
d=56m
r=28m
Ans is 28m
Option is (9)

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Rahul Sinha   8 years AGO

Area of the park = 4550
area excluded fountain = 2086
area of fountain = 2464
R^2 = 2464 * 7/ 22
R = 28 m

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Mridula Shaw   8 years AGO

Area of Park=70*65=4550 m^2
Area of fountain=4550-2086=2464 m^2
Thus,
Pi*r^2=2464
r^2=2464/pi
=>r=28 m

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Devendra Marghade   8 years AGO

Let radius of circular fountain be 'r' m. then
Area of the fountain=Pi*r^2=(70*65) - 2086=2464
r^2=2464/(22/7)=784
r=28
Option 9)

Like? Yes | No (2)