Question Number 89270 by jagoll last updated on 16/Apr/20
$${what}\:{is}\:{the}\:{maximum}\: \\ $$$${perimeter}\:{of}\:{a}\:{parallelogram}\: \\ $$$${ABCD}\:{which}\:{inscribed}\:{the}\: \\ $$$${ellipse}\:\frac{{x}^{\mathrm{2}} }{\mathrm{4}}\:+\:{y}^{\mathrm{2}} \:=\:\mathrm{1}\:? \\ $$