Question

Kindly answer fast..

Answer 1

Answer:

I don't But I know This Like another Problem I mean Example

Step-by-step explanation:

ABCD is a parallelogram

⇒  ∠A+∠B=180o              [ Sum of adjacent angles of parallelogram are supplementary ]

⇒  21∠A+21∠B=2180o

⇒  ∠OAB+∠OBA=90o

In △AOB

⇒  ∠OAB+∠AOB+∠OBA=180o

⇒  ∠AOB=180o−(∠OAB+∠OBA)

⇒  ∠AOB=180o−(∠OAB+∠OBA)

⇒  ∠AOB=180o−90o

∴  ∠AOB=90o