In the given figure, identify the right angle.
∠ABC
∠CAB
∠ACD
∠ADB
We know that, if an angle measures 90o it is called a right angle. From the figure, we see that ∠ADB=90∘. Hence, ∠ADB is a right angle.
In a parallelogram ABCD, the diagonals bisect each other at O. If ∠ABC=30∘,∠BDC=10∘and∠CAB=70∘.
Find: ∠DAB,∠ADC,∠BCD,∠AOD,∠DOC,∠BOC,∠AOB,∠ACD,∠CAB,∠ADB,∠ACB,∠DBC and ∠DBA.