It is geometric because it is increasing by a common factor. If you multiply the previous number by 6 you receive the next number. If it were arithmetic you would add the number, not multiply.
Yes, for triangles to similar two angles have to be the same, in this case, they both have 55 and 30 degrees), this makes the third angle the same. Triangles angles add up to 180 degrees and if you subtract 30 and 55 from 180..
180-30=150-55=95
95+30+55=180
The answers are B and D hope this helps.