Given: angle abd is congruent to angle dbc are complementary
prove: angle abc is a right angle
reasons?

∠ABD ≅ ∠DBC - Given.

∠ABD and ∠DBC are complimentary angles - Given.

∠ABD + ∠DBC = 90° - Definition of complimentary angles.

∠ABD + ∠DBC = ∠ABC - Angle addition postulate.

∠ABC = 90° - Substitution property.

∠ABC is a right angle - Definition of a right angle.

~Hope this helps!~