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← JEE Main 2022 · 29 Jul · Shift 2
MathematicsSingle correct+4 / -1Question 14 of 90

JEE Main 2022 · 29 Jul · Shift 2, Mathematics question 14

Let Q be the foot of perpendicular drawn from the point P (1, 2, 3) to the plane x+2y+z=14x+2y+z=14. If R is a point on the plane such that ∠PRQ = 60°, then the area of ΔPQR is equal to :

Choose one option
Answer and worked solution

Official answer: B

PQ =∣1+4+3−14∣6=6=\dfrac{|1+4+3-14|}{\sqrt6}=\sqrt6. With the angle 60° at R, QR=PQtan⁡60°=2QR=\dfrac{PQ}{\tan60°}=\sqrt2.

Area 126⋅2=3\frac12\sqrt6\cdot\sqrt2=\sqrt3.

(B)