P=2(L+W)
given
L=4n
L=2W
so
4n=2W
2n=W
P=2(L+W)
P=2(4n+2n)
P=2(6n)
P=12n
the perimtiter is 12n
that is twice of that of an equilateral triangle
12n/2=6n
an equilateral triangle has 3 sides of equal length
6n/3=2n
the length of 1 side of the triangle is 2n
