Question

∠a≅∠b, ∠c≅∠b given
∠b≅∠c symmetric prop.
∠a≅∠c?
m∠a = m∠c def. of ≅ ∠s
what is the missing justification?
reflexive property
symmetric property
substitution property
transitive property

Explanation:

The transitive property states that if a = b and b = c, then a = c. Here, since ∠A≅∠B and ∠B≅∠C, ∠A≅∠C by transitive property.

Answer:

transitive property