en application du th de Thalès
FG/FE = FH/FD = GH/De
1300 / FD = 1200/800
FD = ( 1 300 * 800 ) / 1 200 = 867 m arrondi au m
FG² = 1 200² + 1 300 ²
FG² = 3130000
FG = √ 3 130 000 = 1770 m arrondi unité
867 + 1 300 + 1 200 + 1 770 + 1700 + 800 = 7 637 m
distance totale parcourue = 7 637 x 7 = 53 459 m = 53 km