Which pair of triangles must be similar? Group of answer choices

Triangles 1 and 2 each have a 350 angle.

Triangles 3 and 4 are both isosceles. They each have a 400 angle.

Triangle 5 has a 300 angle and a 900 angle. Triangle 6 has a 300 angle and a 700 angle.

Triangle 7 has a 500 angle and a 250 angle. Triangle 8 has a 500 angle and a 1050 angle.