1.7(10^−13)(3.5)(10^25)

=1.7(1/10000000000000)(3.5)(10²⁵)

=(0)(3.5)(10^25)

=0(10^25)

=(0)(1e+25)

=7.263183593750001e+21/1220703125

< 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⭐

add an image

step-by-step explanation: