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If area of a triangular face BCD of a re...

If area of a triangular face BCD of a regular tetrahdedron ABCD is `4sqrt(3)` sq. units, then the area of a triangle whose two sides are represented by vectors `vec(AB)` and `vec(CD)` is

A

6 sq. units

B

8 sq.units

C

12 sq. units

D

16 sq.units

Text Solution

Verified by Experts

The correct Answer is:
B

ar (BCD) `=sqrt(3)/4a^(2)=4sqrt(3)`
`rArr a=4`
Vectors `vec(AB)` and `vec(CD)` are perpendicular
`therefore ar(trianglePQR) = 1/2 xx 4 xx 4=8`
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