# Thread:

1. ## Finding area of 3D triangle

As you've probably guessed, I've started multi-variable calculus. I'm struggling a bit to wrap my head around it.

I'm sure this is an easy question, but I don't know where to begin.

Find the area of the triangle with vertices at A(1,1,1), B(2,3,4), C(5,2,6)

Any help is appreciated.

2. Originally Posted by maxreality
Find the area of the triangle with vertices at A(1,1,1), B(2,3,4), C(5,2,6).
Hint: The area is equal to $\tfrac12AB\cdot AC\cdot\sin A$, which is half the length of the cross product vector $\vec{AB}\times\vec{AC}$.

3. Got it! Terribly easy once I worked through it. I think I'm trying to visualize and look to deep when the answer isn't as complicated as I'm making it.

Thanks!
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