Number 1 Not similar
Number 2: not similar since 9/8 different from 15/10
Number 3: they are similar since they are issoceles triangles with the same exact angles: A A A is the theorem that supports the similarity
Number 4: Not imilar since 12/9 is different from 9/6
Number 5: Yes, they are similar since 24/12 = 18/9 = 10/5 all have rate of 2/1 Use S S S
Number 6: Yes, they are similar since 10/8 = 5/4 and they share a same angle. so this is S A S