How do you prove the equivalence for algebraic and geometric definition for both dot and cross product?

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How do the algebraic and geometric formulas of dot and cross product relate to each other? I have seen the proof for 2 dimensions but how do we generalize it to $n$ dimensions? Is there a way to prove it without the cosine law? That proof feels like a chicken and egg proof as some use vectors to prove cosine rule and vice versa.

Proof for 2 dimensions: Proof of equivalence of algebraic and geometric dot product?