Question 1006880
400 length split into x and y.
Each of these, becomes perimeter x for smaller field, and perimeter y for large field.


Each is square shape, so  side length for small field is {{{x/4}}}; side length for large field is {{{y/4}}}.


{{{(y/4)^2=9*(x/4)^2}}}, from second part of the description.
{{{y^2/16=(9/16)x^2}}}
{{{y^2=9x^2}}}



The original 400 cm length also allows the equation, {{{x+y=400}}}.


Solve this system for x and y:
{{{system(x+y=400,y^2=9x^2)}}}


{{{system(x+y=400,y=0+- 3x)}}}


{{{x-3x=400}}}----this option is meaningless.


{{{x+3x=400}}}
{{{4x=400}}}
{{{highlight(x=100)}}}, {{{highlight(y=300)}}}.