Question

The vectors from origin to the points A and B are $\vec { B } = 2 \hat { i } + \hat { j } - 2 \hat { k }$ respectively. The area of the triangle OAB be

• A. $\frac { 5 } { 2 } \sqrt { 17 }$sq.unit
• B. $\frac { 2 } { 5 } \sqrt { 17 }$ sq.unit
• C. $\frac { 3 } { 5 } \sqrt { 17 }$ sq.unit
• D. $\frac { 5 } { 3 } \sqrt { 17 }$ sq.unit

Answer 1

Answer: (A)

$\frac { 5 } { 2 } \sqrt { 17 }$sq.unit

Answer 2

Given $\overrightarrow { O A } = \vec { a } = 3 \hat { i } - 6 \hat { j } + 2 \hat { k }$ and

$\overrightarrow { O B } = \vec { b } = 2 \hat { i } + \hat { j } - 2 \hat { k }$

$= ( 12 - 2 ) \hat { i } + ( 4 + 6 ) \hat { j } + ( 3 + 12 ) \hat { k }$

$= 5 \sqrt { 17 }$

Area of sq.unit.