panjang:lebar persegi panjang = 4:3,jika kelilingnya 42cm,maka panjang dan lebar adalah..

Diketahui:
Keliling (K) = 42 cm
Panjang (p) = 4x
Lebar (l) = 3x

Ditanya:
p = ????
l = ?????

Jawab:
K = 2(p + l)
42 = 2(4x + 3x)
42/2 = 4x + 3x
21 = 7x
x = 21/7
x = 3

Jadi,
p = 4x
p = 4(3)
p = 12 cm

l = 3x
l = 3(3)
l = 9 cm

Panjang = 4/14 x 42 = 12
lebar = 3/14 x 42 = 9
*smg membantu