Respuesta :

angstar4
Width of a rectangle is half its length:
2w = l
Perimeter is 36
2w + 2l = 36

Plug first equation into second (substitution)

2w + 2(2w) = 36
2w + 4w = 36
6w = 36
w = 6

Plug back into first equation to solve for l

2(6) = 12 = l