Solve with working much appreciated!

1.75 mm

Step-by-step explanation:

Example - 20÷20 = 1

< 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⭐

answer: 8d

step-by-step explanation:

45+5= 50+5=55+5=60