Question 913807
x, short side
y, mid side
z, longest side
perimeter, x+y+z


{{{system(x+y+z=2z,z=4+4x,y=-8+z)}}}


Substitute for z in the perimeter and y equations and simplify (steps not shown here):


Resulting system,
{{{system(3x-y=-4,4x-y=4)}}}
Subtracting one equation from the other, find that {{{highlight(x=8)}}}.


Use x to find value of z:
{{{z=4+4*8}}}
{{{z=32+4}}}
{{{highlight(z=36)}}}


Use that z to find y value:
{{{y=z-8}}}
{{{y=36-8}}}
{{{highlight(y=28)}}}


Side lengths from shortest to longest: 8, 28, 36.