Sorry. Cannot wait for the discussion to be posted later.
here is the question:
373. PS. Which lenghts of the following lratios can form a triangle:
(1) 1:1:3
(2) 1:3:5
(3) 2:2:3
Can not remember all, but it can be useful to think a little bit. I selected (1), not sure.
I would choose 3. Since the sum of any two sides should be greater than the third one and the diff between any two sides should be less than the third one, too. It seems only 3 will satisfy both. Am I right? Thanks | 
