That is the gift of the 107. Go download it. Draw the first triangle. And begin.
Unlike a textbook that dumps formulas on you, this set builds your "geometric intuition." Conciseness: 107 geometry problems pdf
The last problem is legendarily difficult. It often involves a combination of radical axes, homothety, and inversion. Completing #107 is a rite of passage. Many solvers frame the last page of their handwritten notes. That is the gift of the 107
Expect a heavy emphasis on cyclic quadrilaterals, power of a point, homothety, and inversion. The "Aha!" Factor: power of a point
Unlike a textbook that teaches you how to draw an altitude, this PDF assumes you know the basics. It exists to teach you why drawing that specific altitude unlocks the entire solution.