A circular path runs around a circular flower bed .If the circumference of the flower bed and the path are 88 m and 132 m respectively, find the width of the path and the area of the path.

Dear Student,

Circumference of a circle is given by 2πr, here r is the radius.
Circumference of the first circle is given as 88cm,
So 2πr = 88cm
Or 2⨯22/7 ⨯r =88
Or r = 14cm

Circumference of the second circle is given as 132cm
So 2πR =132
Or 2⨯22/7 ⨯R =132
Or R = 21cm

Thus,
Width of the path=21cm-14cm = 7 cm

As these circles are concentric to each other, Hence 
 
Area of the ring is given by = Area of bigger circle - area of smaller circle
Area of a circle is given by πr2 
Hence area of the ring =  π(21)2(14)2 
= π(212-142)
As (a2-b2 ) = (a-b)(a+b)
So π(21+14)(21-14)
= 22/7 (35)(7)
= 770cm2 
Hence area of the ring is given by 770cm2  .

Hope this would have clear your doubt. Do let us know in case of any further concerns.
 

  • 5
circumference =2¶r
(¶=22÷7 ie pi )
= 2¶r= 88
2×22÷7×r = 88
r= (88×7) ÷ (22×2)
r=14
(this one is flower bed)

2¶r= 132
2×22÷7×r =132
r=(132×7)÷(22×2)
r=21
(this one is path)


now take out the area using the radius

(flower bed) r=14
area =¶r^2
22÷7 × 14×14 =616
=616 sq m

(outer circle ) r=21
area =¶r^2
22÷7×21×21=1386
=1386 sq m

subtract the areas

area of outer circle-area of flower bed=area of path
1386-616=770
area of path is 616 sq m


please ask if its not clear
  • 1
width of path = 132-88
=44
  • 0
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