A Solution to Crux Mathematicorum Problem 5031
A concise incircle-inversion proof using contact-chord midpoints and a cyclic quadrilateral, presented without reproducing the original problem statement.
A study of form, relation, and proof
ELEMENTARY
GEOMETRYBeauty in Problems, Proofs, and Diagrams
A growing collection of Euclidean geometry: carefully written solutions, closely observed configurations, and precise diagrams. The emphasis is on seeing why a configuration works.
ENGLISHPROBLEMS · PROOFS · DIAGRAMS
Selected solution
A Solution to Crux Mathematicorum Problem 5021
A direct-similarity generalization proved with Pappus's theorem and a radical axis, presented without reproducing the original problem statement.
Read the solution
More solutions
Further problem solutions
A Solution to Crux Mathematicorum Problem 5088
A concise angle-chasing proof through tangency and cyclic quadrilaterals, presented without reproducing the original problem statement.
A Solution to Crux Mathematicorum Problem 5098
A unit-circle complex proof that reduces two geometric conditions to the same algebraic equation, presented without reproducing the original problem statement.