Vector Algebra Question - CBSE

Question

Area of a triangle with vertices $A(1, 1, 1), B(1, 2, 3), C(2, 3, 1)$ is:
(a) $\dfrac{\sqrt{21}}{2}$ sq. units
(b) $\sqrt{21}$ sq. units
(c) $\dfrac{21}{2}$ sq. units
(d) $\dfrac{\sqrt{21}}{4}$ sq. units

Accepted Answer

$\vec{AB} imes \vec{AC} = -4\hat{i} + 2\hat{j} - \hat{k} \Rightarrow ext{Area} = \dfrac{\sqrt{21}}{2}$. [1.0 Mark]

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🎯 Official CBSE Marking Scheme:
Evaluating triangle area $= \sqrt{21}/2$ sq. units: 1.0 Mark

Question:

Step-by-Step Solution

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