Given: AOC is congruent to AOB Prove: ACO is congruent to ABO
ΔAOC ≅ ΔAOB → AO ≅ AO, AC ≅ AB, CO ≅ BO (corresponding parts of congruent triangles are congruent).
Since AC ≅ AB, AO ≅ AO, and CO ≅ BO, ΔACO ≅ ΔABO (side-side-side)