1. New right triangle triples can be found by doubling, tripling, etc. an old right triangle triple.

3-4-5 5-12-13 7-24-25 9-40-41
6-8-10 10-24-26 14-48-50  
9-12-15 15-36-39    
12-16-20      
15-20-25      
18-24-30      
21-28-35      
24-32-40      
27-36-45      
30-40-50