Question

ABCD is a rectangle with ∠ABD = 40°. Determine ∠DBC.

Answer 1

Each angle of a rectangle = 90°

So, ∠ABC = 90°

∠ABD = 40° (given) 

Now, ∠ABD + ∠DBC = 90°

40° + ∠DBC = 90°

or ∠DBC = 50°