The x - coordinate of the incentre of the triangle that has the coordinates of midpoints of its sides as…

The x-coordinate of the incentre of the triangle that has the coordinates of midpoints of its sides as 0,1, 1,1 and 1,0 is
  1. 1+2
  2. 1 - 2
  3. 2 + 2
  4. 2 - 2

Solution



Let x1, y1, x2, y2 and x3, y3 be the vertices of a triangle,

So,
x1+x2=0, x2+x3=2, x3+x1=2 [mid point formula x1+x22 ]

Similarly,

y1+y2=2, y2+y3=2, y3+y1=0

So, the vertices are 0,0, 0,2, 2,0.

We know that x-coordinate of incentre x¯=ax1+bx2+cx3a+b+c   

a=2,b=2,c=22,x1=0,x2=2,x3=0

  x¯=0+4+02+2+22

 x¯=2-2

Asked in: JEE Main 2013 (07 Apr)

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