Hi... Can anyone help me out with the below question?
Thanks....
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 shovan85
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If it were a complete circle then the missing part of the circle is 1/4 of the circle.
Full circle subtends 360 deg in center.
1/4 of the circle subtends 90 deg in center.
Now draw a triangle with the straight line shown 12 ft as base. Then it will be a isosceles triangle with 90 at origin. It becomes isosceles because the other two sides are radius.
Thus r^2 + r^2 = 12^2
=> 2r^2 = 144
=> r^2 = 72
=> r = 6(2)^1/2
Thus the perimeter of circle = 2 * pie * 6(2)^1/2
Then 3/4th of the circle perimeter = 3/4 * [2 * pie * 6(2)^1/2]
Thus answer = 9 * pie * (2)^1/2
IMO C
Full circle subtends 360 deg in center.
1/4 of the circle subtends 90 deg in center.
Now draw a triangle with the straight line shown 12 ft as base. Then it will be a isosceles triangle with 90 at origin. It becomes isosceles because the other two sides are radius.
Thus r^2 + r^2 = 12^2
=> 2r^2 = 144
=> r^2 = 72
=> r = 6(2)^1/2
Thus the perimeter of circle = 2 * pie * 6(2)^1/2
Then 3/4th of the circle perimeter = 3/4 * [2 * pie * 6(2)^1/2]
Thus answer = 9 * pie * (2)^1/2
IMO C
If the problem is Easy Respect it, if the problem is tough Attack it

 Newbie  Next Rank: 10 Posts
 Posts: 3
 Joined: 02 Dec 2010
shovan85 wrote:If it were a complete circle then the missing part of the circle is 1/4 of the circle.
Full circle subtends 360 deg in center.
1/4 of the circle subtends 90 deg in center.
Now draw a triangle with the straight line shown 12 ft as base. Then it will be a isosceles triangle with 90 at origin. It becomes isosceles because the other two sides are radius.
Thus r^2 + r^2 = 12^2
=> 2r^2 = 144
=> r^2 = 72
=> r = 6(2)^1/2
Thus the perimeter of circle = 2 * pie * 6(2)^1/2
Then 3/4th of the circle perimeter = 3/4 * [2 * pie * 6(2)^1/2]
Thus answer = 9 * pie * (2)^1/2
IMO C
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