If the incentre of an equilateral triangle is 1 , 1 and the equation of its one side is 3 x + 4 y + 3 = 0 ,…

If the incentre of an equilateral triangle is 1,1 and the equation of its one side is 3x+4y+3=0, then the equation of the circumcircle of this triangle is:
  1. x2+y2-2x-2y-2=0
  2. x2+y2-2x-2y+2=0
  3. x2+y2-2x-2y-7=0
  4. x2+y2-2x-2y-14=0

Solution



3x+4y+3=0

Since, for equilateral triangle centroid in center and circumcenter is the same therefore length of AB=31+41+332+42

=105=2

R=2AB=4

As centroid divide median in the ratio 2:1

Centre of the circle would be 1,1

∴  Answer is x2+y2-2x-2y-14=0

Asked in: JEE Main 2015 (11 Apr Online)

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