Q. 18 A

# Using vectors, find the area of ΔABC whose vertices are

A(1, 1, 2), B(2, 3, 5) and C(1, 5, 5)

Answer :

Through the vertices we get the adjacent vectors as,

The area of the triangle = , where a and b are it’s adjacent sides vectors.

Area =

Here,

We

have

⇒

Thus, substituting the values of ,

in equation (i) we get

⇒

⇒

⇒ sq units

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