Question

Keliling sebuah persegi panjang 240 cm jika perbandingan panjang & lebar 7 : 5. tentukan luas persegi panjang ?

tolong yaa

Answer 1

Keliling = 2(p+l)
240/2 = p+l
120 = p+l

p = 7/12 x 120 = 70 cm
l = 5/12 x 120 = 50 cm

maka luas persegi panjang = p x l = 70 x 50 = 3500 cm²

Answer 2

Keliling persegi panjang = 2 (p + l)
= 2 (7x + 5x)
= 2 (12x)
= 24x

24x = 240
x = 240 / 24
x = 10

panjang = 7 * 10 = 70 cm
lebar = 5 * 10 = 50 cm

luas = 70 * 50
= 3500 cm²