perbandingan panjang dan lebar persegi panjang 3 : 2 . Jika keliling persegi panjang 60 cm , luas persegi panjang adalah... cm?

Panjang = 3a
lebar = 2a

Keliling = 2p + 2l
60 cm = 2(3a + 2a)
60 cm = 2(5a)
60 cm = 10a
60 cm / 10 =a
6 cm = a

panjang = 3a = 3(6 cm) = 18 cm
lebar = 2a = 2(6 cm) = 12 cm

Luas
= pl
= (18 cm) (12 cm)
= 216 cm²

K = 2 x ( p+l )
60 cm = 2 x ( p+l )
60 : 2 = ( p+l )
30 = 3 : 2 ( perbandingan )
p = 30 x 3/5
p = 18

l = 30 x 2/5
l = 12

luas persegi panjang = p x l
18 x 12 = 216cm persegi.