Perhatikan gambar Persegi panjang abcd AB 4x-1 BC 2x jika keliling persegi panjang abcd 62 cm hitunglah a. panjang dan lebar persegi panjang abcd b. panjang dia

k = 2 × ( AB + BC )
62 = 2× ( 4x-1 + 2x )
62/2 = 6x -1
31 + 1 = 6x
x = 32/6

AB = 4×32/6 -1 = 128/6 - 6/6 = 122/6 cm
BC = 2×32/6 = 64/6 cm

AC = √(122/6)² + (64/6)² = √(14.884/36 + 4.096/36) = √18.980/36 = 22,96 cm

Luas = 122/6 x 64/6 = 7.808/36 = 216,9 cm²