Please help! I don't really understand this :/

The answer is 19 (See picture below for explanation)

OR:

2 x () ÷ 8 + (5 x 3)

< 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⭐

150.6

all i did was i multiplied 5.02 by 30