JEE Main201910 Apr 2019Morning ShiftMathematicsThree Dimensional GeometryActual
If Q ( 0 , - 1 , - 3 ) is the image of the point P in the plane 3 x - y + 4 z = 2 and R is the point ( 3 , - 1 , - 2 ) , then the area (in sq. units) of Δ P Q R is
Options
- A91 4
- B91 2
- C2 13
- D65 2
Correct answer
B. 91 2
Step-by-step solution
Given, equation of plane is 3 x - y + 4 z - 2 = 0 . Distance, P M = 1 - 12 - 2 9 + 1 + 16 = 13 2 P R = 9 + 1 = 10 ∴ R M = 10 - 13 2 = 7 2 ∴   Area of ∆ P Q R = 2 1 2 × P M × R M = 2 1 2 × 13 2 × 7 2 = 91 2