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# 3D triangle surface

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Does anyone know how to calculate the surface of a 3D triangle? The given data is 3 points in 3D space. *feels dumb :\$*

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define better the term surfaces or at least what exactly you want to calculate do you mean area of a surface in space ?

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I mean the size of the triangle (not the line around it, but the surface size in cm²)

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I cant understand what you really want. Are you talking about surface area of trianglemas you said you want it in cm cm. Then its very famous formula used in school math which i forgot too HAHA.

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It seems that I don''t know the proper translation to English, but I thought it was (base*height)/2 for regular 2D surface size. I need that formula in 3D

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oh yes i remembered it. It is

Surface Area of Tringle = 1/2 x Height x Base

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Area(A,B,C)=|(B-A) x (C-A)|/2

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quote:
Original post by Anonymous Poster
Area(A,B,C)=|(B-A) x (C-A)|/2

Is the "x" sign the dot product of the two resulting vectors?

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x is dot, sure area is a scalar quantity. and B-A and C-A are not vectors. They are points.

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quote:
Original post by DirectXXX
x is dot, sure area is a scalar quantity. and B-A and C-A are not vectors. They are points.

True, but if you consider a point to be a vector from (0,0,0) to (Ax, Ay, Az), then that''s a correct consideration too The dot product is also performed on vectors, not on points. Thanks for your help.

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