Monkeymohawk57, I recommend doing your math on your own, but I will help you with this question.
Note the ratios between the side lengths: 5:3 and 15:9, which can be simplified to 5:3 as well. Because they both have the same ratios of sides, they are similar figures.
The answer is "These two figures are similar because 5/3 equals 15/9". Best of luck.