Which of the following statements are true about the figure given below?
∠DBC = 180o
∠CBA = 90o
∠CBA and ∠DBA are supplementary.
Here ∠ABD and ∠ABC are supplementary, since they lie on a straight line.
Hence ∠DBC = 180∘
As shown, ∠ABC = 90∘
∴∠ ABD = 180 - ∠ ABC = 180 - 90 = 90∘