Dik: keliling segitiga= 105cm

K = 105
(4+5+6)x = 105
15x = 105
x = 105/15
x = 7 cm

panjang= 4x = 4×7 = 28 cm
lebar = 5x = 5×7 = 35 cm
tinggi = 6x = 6×7 = 42 cm

sisi terpanjang 42 cm