Question

question number 16 prove that x is equal to 3 y ​

Answer 1

OB=BC

BOC=BCO=y

Ext. OBA=BOC+BCO=2y

OA=OB

OAB=OBA=2y

Ext. AOD=OAC+ACO=OAB+BCO=3y

Hence, x=3y

Answer 2

Answer:

Step-by-step explanation:

As BC=OB,  ∠BCO = ∠BOC = y°

sum of angles in a triangle = 180°

∠OBC+∠BOC+∠BCO = 180°

∴ ∠OBC=180-2y°

∠OBA + ∠OBC = 180°

∴ ∠OBA = 2y°

As ABO forms a bi-lateral traingle, ∠OBA=∠OAB

∴ ∠OAB = 2y°

∠AOB+∠ABO+∠OAB = 180°

∠AOB + 2y° + 2y°  = 180°

∠AOB = 180 - 4y°

∠AOD + ∠AOB + ∠BOC = 180°

x° + (180° - 4y°) + y° = 180°

∴ x° = 3y°