Which pair of triangles must be similar? Triangles 1 and 2 each have a 35^{\circ}35
∘
angle.

Triangles 3 and 4 are both isosceles. They each have a 40^{\circ}40
∘
angle.

Triangle 5 has a 30^{\circ}
∘
angle and a 90^{\circ}
∘
angle. Triangle 6 has a 30^{\circ}
∘
angle and a 70^{\circ}
∘
angle.

Triangle 7 has a 50^{\circ}
∘
angle and a 25^{\circ}
∘
angle. Triangle 8 has a 50^{\circ}
∘
angle and a 105^{\circ}
∘
angle.