How do I vote someone Brainliest? I'm new, and I can't seem to figure it out.

you will able to mark someone brainliest when two persons already given the answer. if two persons give the answer then at the top of every answer there is written " mark as brainliest" . so which answer you like you have to click on that.

Step-by-step explanation:

Hope this helped ;)o(*￣▽￣*)o

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐

the first one, all those points on the line just make a strait line.