Question 1063503
*Simpler method shown below at bottom


x, the two larger sized lots area together
y, the three smaller sized lots area together
{{{x+y=43560}}}
and 
{{{(x/2)/(y/3)=5/4}}}



Solve that as a system for x and y.
You are interested then in {{{x/2}}}, the size of each of the larger lots and {{{y/3}}}, the size of each of the three smaller lots.




NOT THE ONLY WAY


* This may be simpler.
s, size of each small lot
b, size of each big lot
{{{system(3s+2b=43560,b/s=5/4)}}}
Solve this system for s and b.