With experience you discover that the proofs of the first two years almost always revolve around a few recurring situations. Learning to recognise them in the figure is half the work.
Observation — The 5 most frequent moves in proofs
The five situations that recur in the majority of first-two-years Euclidean geometry proofs.
These five situations recur in the majority of first-two-years Euclidean geometry proofs. Learn to recognise them in the figure!
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Topics: Euclidean geometry
Concepts: Alternate interior angles · Vertically opposite angles · Exterior angle · Proof · Isosceles triangle
Skills: Proving · Synthetic geometry