Question

Suatu Persegi panjang keliling 80 cm. jika lebarnya adlh empat kurangnya dan panjang. hitung panjang dan lebar dan luas.

Answer 1

2(p + l) = 80
p + l = 40
l = p - 4
substitusi
p + p - 4 = 40
2p - 4 = 40
2p = 44
p = 22 cm = panjang
l = 22 - 4 = 18 cm = lebar
luas = p x l = 22 x 18 = 396 cm²

Answer 2

2p + 2l = 80 ---> 2p + 2(p - 4) = 80 --> 2p + 2p - 8 = 80 --> 4p = 88 --> p = 22 cm
l = p - 4 = 22 - 4 = 18 cm
L = p x l = 22 x 18 = 396 cm2