A mathematical interlude in three parts

i - LUCKY FOR SOME    
Seventy-seven  
divided by eleven:    
forty-nine's square root.
    
ii - A PRIME NUMBER EQUAL TO THE SUM OF FOUR CONSECUTIVE, SMALLER PRIMES    
Take a dozen, a trio and quintet;    
multiply them to see what you get.    
Then add on a seven,    
divide by eleven:    
a sum of four primes! Got it yet?    
   
iii - VIVIDLY NUMERICAL    
Take the numerals V, I and V;    
add them up and then take away three.    
Next, this number gets squared,    
and then quartered (or shared);    
the result's twice (two cubed) QED!