I'm sure this is simple math. my brother asked for on his homework and i've never done any of these common core problems. so if you can link me a video that explains it or give me an explanation on how to do these that would be great.

< 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⭐

so then what are you asking?

step-by-step explanation:

22

step-by-step explanation:

22