Respuesta :

Answer:

∠DBC = 40°

Step-by-step explanation:

∠5 = ∠3 + ∠4 = 180° - ∠6 . . . . relationship of angles at a transversal, vertical angles

∠3 = 180° - ∠1 - ∠2 . . . . . . sum of angles of a triangle

Then

∠4 = 180° - ∠6 - (180° - ∠1 - ∠2) = ∠1 +∠2 -∠6 . . . . substitute for ∠3

∠4 = 65° +60° -85° = 40°

∠4 = ∠DBC = 40°

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