Answer:
No 4: the triangle are similar by congruency SAS(side angle side)
No 5: this is also similar by SAS
No 6: this is similar by AAS ( angle angle side)
No 7: this is similar by RHS ( right angle hypotenuse one side )
No 8: this pair of triangles are not similar
No 9: this is similar by SAS
No 10: this pair of triangles are similar by SAS ( side side side)
No 11: this triangle is similar by SSS
No 12: this triangle is similar by SSS