I think it’s going to be 7! Because since the other triangle is 1 and 3 it’s just 2 more so I just added to more to 5 getting me 7!! I think lol
Recall the double angle identity:
With 
measuring between 0º and 90º, we know 
. So from the Pythagorean identity, we get
Then
I always feel drawn to the number 2 for some reason because it is in the middle between 2 and four and usually when given an option to pick a number I never pick a number that they say. Personally I just feel drawn to pick the number 2 its a nice even number and perhaps could be lucky :)
