Persegi panjang mempunyai perbandingan panjang : lebar = 7:5. Jika kelilingnya 120 cm, maka lebar persegi panjang itu adalah... a.20 cm, b.21 cm, c.25 cm, d.28 cm
Tolong jawab pakai cara ya! :)
AnggitaSeveners
Misal x p : l = 7 : 5 p = 7x l = 5x K = 120 cm K = 2(p+l) 120 cm = 2(7x + 5x ) 120 cm = 24x x = 120/24 x = 5 lebar = 5x = 5 x 5 = 25 cm
p : l = 7 : 5 p = 7x l = 5x
K = 120 cm
K = 2(p+l)
120 cm = 2(7x + 5x )
120 cm = 24x
x = 120/24
x = 5
lebar = 5x = 5 x 5 = 25 cm
(p+l) = 120÷2 = 60 cm
Jumlah perbandingan = 7+5 = 12
Lebar = 5/12 x 60 = 5 x 5 = 25 cm