# Conflict

Geometry Level 3

Find the value of $$a$$ such that the points with position vectors are co-planar. Vectors are:

$$3\vec i+6\vec j+9\vec k$$

$$1\vec i+2\vec j+3\vec k$$

$$2\vec i+3\vec j+\vec k$$

$$4\vec i+6\vec j+a\vec k$$

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