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← JEE Main 2022 · 26 Jul · Shift 1
MathematicsInteger+4 / -1Question 30 of 90

JEE Main 2022 · 26 Jul · Shift 1, Mathematics question 30

Let Q and R be two points on the line x+12=y+23=z−12\dfrac{x+1}2=\dfrac{y+2}3=\dfrac{z-1}2 at a distance 26\sqrt{26} from the point P(4,2,7)P(4,2,7). Then the square of the area of the triangle PQR is ______.

Answer and worked solution

Official answer: 153

Foot of the perpendicular from P on the line: (−1+2t,−2+3t,1+2t)(-1+2t,-2+3t,1+2t) with t=2t=2 gives M=(3,4,5)M=(3,4,5), PM2=1+4+4=9PM^2=1+4+4=9.

Half-base. QM2=26−9=17QM^2=26-9=17.

Area² =(QM⋅PM)2=17×9=153=(QM\cdot PM)^2=17\times9=153.

Answer: 153