Perbandingan panjang dan lebar persegipanjang 9:5 jika kelilingnya 84 m maka luasnya

Mis , p = 9x , l = 5x
K = 2(p+l)
84 = 2(9x + 5x)
84/2 = 14x
42 = 14x
x = 42/14 = 3

P = 9 x 3= 27 cm
l = 5 x 3 = 15 cm

L = p x l
= 27 x 15
= 405 cm^2