Answer:
AAA similarity
Explanation:
Similarity of triangles:
Two triangles are similar, if they have (i) all their angles equal (ii) corresponding sides ate in the same ratio.
AAA , SAS and SSS are the three ways to find if two triangles are similar.
∠A = ∠Q = ∠Y = 50°
∠B = ∠P = ∠Z = 60°
∠C = ∠R = ∠X = 70°
So,
ΔABC ~ ΔQPR
ΔPQR ~ ΔZYX
ΔZYX ~ ΔBAC