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Semicircle GMAT Prep
This topic has expert replies
Its tricky but easy.
Let BAO=x
As AB=OC, AB=OB (OB=OC radii)
So, AOB=x
So, OBC=2x (exterior angle)
BCO=OBC=2x
BOC=180-x-COD and BOC=180-4x
From 1, COD=60
So, BOC=120-x
So, 120-x=180-4x
Thus, x=20 SUFFICIENT
From 2, BCO=40
So, 2x=40
And x=20 SUFFICIENT
Answer D.
Let BAO=x
As AB=OC, AB=OB (OB=OC radii)
So, AOB=x
So, OBC=2x (exterior angle)
BCO=OBC=2x
BOC=180-x-COD and BOC=180-4x
From 1, COD=60
So, BOC=120-x
So, 120-x=180-4x
Thus, x=20 SUFFICIENT
From 2, BCO=40
So, 2x=40
And x=20 SUFFICIENT
Answer D.
