Answer:
60°
Step-by-step explanation:
In similar triangles, the corresponding angles are congruent.
∠O = R
O = 70°
In ΔOMN,
∠O + ∠M + ∠N = 180 {Angle sum property of triangle}
70 + 50 + Ф = 180
120 + Ф = 180
Subtract 120 from both sides,
Ф = 180 - 120
Ф = 60°
