Question 1199219
if
{{{LM=2a}}]
{{{MN=12a}}}
{{{LM=20}}}

then

{{{2a=20}}}
{{{a=10}}}


{{{MN=12a=12*10=120}}}


{{{ LN=20+120}}}
 {{{LN=140}}}

 L____{{{2a}}}_______M__________{{{12a}}}_____________N
|______{{{20}}}______|___________{{{120}}}____________|