The segments CD and AB intersect at point O so that AO = BO, angle AOC = angle BDO. Prove that CO = DO.

Given:
CD∩AB
AO = BO
∠АС = ∠ВDO.
Prove:
CO = DO.
Decision:
ΔAOС = ΔDОВ – along the side and two adjacent corners (second feature), therefore CO = DO, as the corresponding (similar) elements of equal triangles.



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