OG question

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Sun Apr 15, 2007 11:54 pm

OG question

by Ramesh2007 » Sat May 26, 2007 12:10 pm
Can somebody explain me this please.
Attachments
PS-9.JPG

User avatar
Community Manager
Posts: 789
Joined: Sun Jan 28, 2007 3:51 pm
Location: Silicon valley, California
Thanked: 30 times
Followed by:1 members

Legendary Member
Posts: 559
Joined: Tue Mar 27, 2007 1:29 am
Thanked: 5 times
Followed by:2 members

by Cybermusings » Sat May 26, 2007 11:33 pm
One thing can be made out from the stem - AB = OC = OB = radius
Hence Triangle ABO becomes an isoceles triangle....
Statement I : COD = 60 degrees...Hence angle COA = 180-60 = 120 degrees
CBO = Angle BAO + Angle BOA (extrerior angle = sum of remote interior angles) = 2x
Hence angle BAO = BOA = x
Now BOC + BOA = 120
So 180-4x+x = 120
3x = 60; hence x = 20
Hence sufficient

Statement II : If BCO = 40...Then BCO = CBO = 40
Hence ABO = 140 and BAO = BOA = 180 - 140/ 2 = 20
hence sufficient