Three Dimensional Geometry
NCERT Class 12
CBSE
Grade 12
Question:
Show that the lines $\dfrac{x-5}{7} = \dfrac{y+2}{-5} = \dfrac{z}{1}$ and $\dfrac{x}{1} = \dfrac{y}{2} = \dfrac{z}{3}$ are perpendicular.
Step-by-Step Solution
Direction ratios: $(7, -5, 1)$ and $(1, 2, 3)$. [1.5 Marks]
$7(1) + (-5)(2) + 1(3) = 7 - 10 + 3 = 0$. Proved. [1.5 Marks]
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🎯 Official CBSE Marking Scheme:
Extracting direction ratios: 1.5 Marks
Verifying dot product is zero: 1.5 Marks
Correct Answer:
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