Prove geometric results with vectors - visual substitution line
In a parallelogram proof, \(|\mathbf{a}|=7\), \(|\mathbf{b}|=9\), and \(\mathbf{a}\cdot\mathbf{b}=12\). Enter \(|\mathbf{a}+\mathbf{b}|^{2}\).
Worked practice: result and interpretation
Calculate the requested result first, then choose the interpretation that follows from it.
Write a full answer
Now write the response in full, in your own words — this is what the exam asks for. The AI marks it on the same moves you built above (focus, evidence, technique, judgement) and gives feedback on reasoning, evidence, and expression.