Question 264866
2x+2y=p for the rectangle
m+m+m=p for equilateral triangle
the rectangle "p" = the triangle "p"
{{{2x+2y=3m}}} solve for x
{{{2x+2y-2y=3m-2y}}}
{{{2x=3m-y}}}
{{{(2x)/2=(3m-2y)/2}}}
{{{x=(3m-2y)/2}}}or{{{x=(1/2)(3m-2y)}}}