Question

In the given figure, if EC || AB, ∠ECD = 70° and ∠BDO = 20°, then ∠OBD is

विकल्प

• 20°

• 50°

• 60°

• 70°

Answer 1

In the given figure, EC || AB,∠ECD = 70° and  ∠BDO= 20°. We need to find ∠OBD.

Here, EC || AB and CD is the transversal, so using the property, “corresponding angles are equal”, we get

∠AOD = ∠ECD

∠AOD = 70°

Also, using the property, “an exterior angle of a triangle is equal to the sum of the two opposite interior angles”, in ΔOBD, we get, 

∠AOD = ∠OBD + ∠BDO

        70° = ∠OBD + 20° 

∠OBD = 70° - 20°

∠OBD = 50°

Thus,∠OBD = 50° .