Need some answers please to this problem

What two criteria are needed for triangles to be similar

Joseph haydn pet store offers wide variety of leashes for dogs. the store purchases one popular type of leash from its manufacturer for $4.38 each. joseph haydn pets marks up leashes at a rate of 238% of cost. what is the retail price of the popular leash?

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).