Question

Perbandingan panjang dan lebar persegi panjang 9:5, jika kelilingnya 84 m, maka luasnya adalah ?

Answer 1

P : l
9 : 5
9y : 5y

K = 2(p+l)
84 = 2(9y+5y)
84 = 2(14y)
84 = 28y
3 = y

p = 9y = 9 x 3 = 27 m
l = 5y = 5 x 3 = 15 m

L = p x l
L = 27 m x 15 m = 405 m²

Answer 2

Keliling = 2(p+l)
84 = 2(9x+5x)
84=28x
x = 84/28 = 3
panjang = 9 x 3 = 27 m
lebar = 5 x 3 = 15 m
luas = p x l = 27 x 15 = 405 cm²