What is the measure of minor arc ac, given that ab and bc are tangent to
oo?

200°

Step-by-step explanation:

In ΔABO ∠ABO=20°/2=10°

∠BAO=90°

sum of the angles of the ΔABO=180°

90°+10°+x=180°

x=180°-100°=80°

Therefore ∠AOB=80°

By similarity we have ∠COB=∠AOB=80°

Let the arc AC be x

now we know that the whole angle is 360°

x+80°+80°=360°

x=200°

both equations and proportions are better.