Question 857992
perimeter = 4x+20

to get side divide by 4

4(x+5)/4

= (x+5)

diagonal ^2= side 1^2+side2^2   ( Pythagoras theorem)

d^2= (x+5)^2 +(x+5)^2

= 2(x+5)^2


d= {{{sqrt(2)(x+5)}}}