Question

Let for a triangle ABC,
$\vec{AB}=-2\hat{i}+\hat{j}+3\hat{k}$
$\vec{CB}=α\hat{i}+β\hat{j}+γ\hat{k}$
$\vec{CA}=4\hat{i}+3\hat{j}+δ\hat{k}$
If $δ>0$ and the area of the triangle ABC is $5\sqrt6$, then $\vec{CB}.\vec{CA}$ is equal to

• A. 60
• B. 54
• C. 120
• D. 108

Answer 1

Answer: (A)

60

Answer 2

The correct answer is (A) : 60