Perbandingan panjang dan lebar persegi 3:1 jika keliling 72 maka luasnya....

p : l = 3 : 1 maka p = 3l
K = 2p + 2l
72 = 2.3l + 2l
72 = 6l + 2l
72 = 8l
l = 72/8
l = 9 cm

maka p = 3x9 = 27 cm

Luas = p. l = 27 x 9 = 243 cm2

kel. persegi panjang = 2(p+l)
72 = 2(3x+x)
72 : 2 = 3x+x
36 = 4x
x = 36/4
x = 9
panjang = 3x = 3.9 = 27
lebar = x = 9

luas = p×l =27 x 9 = 243