In Fig. 9.43, if EC || AB , ∠ ECD =70° and ∠ BDO =20° , then ∠ OBD is

Question

In Fig. 9.43, if EC || AB , &#x2220; ECD =70&#xB0; and &#x2220; BDO =20&#xB0; , then &#x2220; OBD is

Philoid · Accepted Answer

Given,

EC ‖ AB

∠ECD = 70^o

∠BDO = 20^o

Since,

EC ‖ AB

And, OC cuts them so

∠ECD = ∠1 (Alternate angle)

∠1 = 70^o

∠1 + ∠3 = 180^o (Linear pair)

∠3 = 110^o

In

∠BOD + ∠OBD + ∠BDO = 180^o

∠3 + ∠ODB + 20^o = 180^o

∠ODB = 50^o