3000 + 500 + 60 = 3560
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Your calculator can help you out here if you really have no idea that the exponent of 10 tells you the number of zeros: 10^3 = 1000.
Answer:
∠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!~
