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I am trying to say

Construct $\triangle ABC$ such that the extension of side CB is adjacent to side AB

I am trying to avoid using poor ambiguous vocabularies like "to the right of AB"

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Re-posted answer + comments, per OP's request:


You'll might want to specify that $A, \;B$ and $C$ are three non-colinear points (hence form a triangle), otherwise if A, B and C all lie on a line, then "adjacent" might be ambiguous. Consider, for example,:

Crudely, e.g.,

A________B________C

Then to specify the order in which the points are arranged, add your adjacency stipulation.

Note: While asserting the existence of three non-colinear points asserts the existence of a triangle, some might argue that the converse is not necessarily true. (That is, some might argue that a straight line is a degenerate triangle, but that's probably beyond the scope of your task.)

However, you can justifiably assume that, by definition:

$|AB| + |BC| > |AC| \iff A, B, C \text{ are non-colinear}\; \iff \exists \triangle ABC.$

For example, see this post.

At any rate, in my answer (at the start), I was assuming that you are trying to both define and construct a triangle.

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    It depends on the context - but in my opinion, you are safe with stating exactly what you posted. And yes, adjacent is precisely the word you want. When you asked me to "undelete" what I said, is the content of this answer what you wanted me to undelete?2012-11-08
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It does sound a bit weird, but I guess it's acceptable since it doesn't seem ambiguous.

How about "extend $\overline{CB}$ past $B$" instead?

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    @amWhy, could you "undelete" what you sa$i$d?2012-11-08