Question 381821
Let the length and width be 3x and x, respectively. Since the diagonal is 50, we have

{{{(3x)^2 + x^2 = 50^2 = 2500}}}

{{{10x^2 = 2500}}}

{{{x^2 = 250}}}

{{{x = 5sqrt(10)}}} {{{ 3x = 15sqrt(10)}}}

Therefore the perimeter is {{{40sqrt(10)}}}.