And when you finally solve that IMO geometry problem at 2 AM, you will know exactly why everyone was searching for that PDF.
By internalizing these lemmas, you stop solving problems from scratch and start assembling solutions like a master builder. Titu Andreescu Geometry.pdf
Not just "prove equal," but "prove less than." Problems involving Erdős–Mordell inequality, Euler's inequality, and Weitzenböck's inequality are solved with geometric finesse. And when you finally solve that IMO geometry
In essence, this PDF is a curated collection of: Titu Andreescu Geometry.pdf
If you download a legitimate copy of his geometry materials (often via the AwesomeMath website or institutional access), you will typically find these eight sections: