(i) From the figure:

∠A = ∠P = 60°

∠B = ∠Q = 80°

∠C = ∠R = 40°

Therefore, ΔABC ΔPQR [By AAA similarity]

(ii) The triangles ABC and QRP are similar to each other by SSS similarity

(iii) The given triangles are not similar because the corresponding sides are not proportional

(iv) In triangle MNL and QPR, we have

∠M = ∠Q = 70^o

ΔMNL ~ ΔQPR (SAS similarity)

(v) In triangle ABC and DEF, we have

AB = 2.5, BC = 3

∠A = 80^o

EF = 6

DF = 5

∠F = 80^o

And,

∠B ≠ ∠F

Hence, triangle ABC and DEF are not similar

(vi) In triangle DEF, we have

∠D + ∠E + ∠F = 180^o (Sum of angles of triangle)

70^o + 80^o + ∠F = 180^o

∠F = 30^o

In PQR, we have

∠P + ∠Q + ∠R = 180^o

∠P + 80^o + 30^o = 180^o

∠P = 70^o

In triangle DEF and PQR, we have

∠D = ∠P = 70^o

∠F = ∠Q = 80^o

∠F = ∠R = 30^o

Hence, ΔDEF ~ ΔPQR (AAA similarity)