Focus on the bottom side of the triangle. The first one has a length of 6mm while the second one had a length of 18mm. What is the scale between these 2? 6 times 3 equals 18 so the scale factor is 3 from triangle A (first one) to triangle B (secone one). Now look at the sdie length of both triangles. These would have the same scale factor so muktipky 8 by 3 to get X, which would be 24. To find Y, you need to think what number do you multiply by 3 to get 30. That is the same thing as 30/3 which is 10. Your final answer is X=24 and Y=10.