Answer:
Yes, Yes, Yes
Explanation:
21/14 = 1.5
15/10 = 1.5
Yes, you're increasing both the width and length of the smaller polygon by the same ratio (1.5) to get the larger polygon
21/7 = 3
15/5 = 3
Yes, you're (once again) increasing both the width and length by the same ratio (3)
The larger polygon has been rotated (or so I think)
35/28 = 1.25
25/20 = 1.25
The corresponding sides have been increased by the same ratio (1.25) so they're mathematically similar!