Evaluate or slove each expression [11+(20÷10)]×7

PEMDAS, you can do a quick search on google for images only, there are some nice pictures of it you might like.

we do the grouping first, from innermost to outmost, and peMDAS, we do MD before any AS.

< 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⭐