Question 312788
Let x = the length you need.  


Then, set up a ratio:  {{{ W/L= 16/20=20/x}}}


{{{a/b=c/d}}} means {{{ad=bc}}}


{{{16/20=20/x}}} means {{{16x= 20*20 = 400}}}
{{{x= 400/16= 25 }}} inches.


Dr. Robert J. Rapalje, Retired