MHT CET202313 May 2023Evening ShiftMathematicsThree Dimensional GeometryActual
The incentre of the triangle ABC , whose vertices are A (0,2,1), B (-2,0,0) and C (-2,0,2) , is
Options
- A(- 3 2 , 1 2 , 1 )
- B( 3 2 , 1 2 , 1 )
- C(- 3 2 ,- 1 2 ,-1 )
- D( 3 2 ,- 1 2 ,-1 )
Correct answer
A. (- 3 2 , 1 2 , 1 )
Step-by-step solution
Let a =2 j + k , b =-2 i , c =-2 i +2 k AB =-2 i -2 j - k , BC =2 k aligned & AC =-2 i -2 j + k & | AB |=3,| BC |=2,| AC |=3 aligned Incentre of ABC is given by | AB | c +| BC | a +| AC | b | AB |+| BC |+| AC | aligned & = 3(-2 i +2 k )+2(2 j + k )+3(-2 i ) 3+2+3 & = -12 i +4 j +8 k 8 & =- 3 2 i + 1 2 j + k aligned