bonjour
(EF)² = ( 1 + 3 )² + ( 9 - 1 )² = 4 ² + 8 ² = 16 + 64 = 80
( FG)² = ( - 7 - 1 )² + ( 13 - 9 )² = ( - 8 )² + 4 ² = 64 + 16 = 80
(GH)² = ( - 11 + 7 )² + ( 5 - 13 )² = ( - 4 )² + ( - 8 )² = 16 + 64 = 80
( HE)² = ( - 3 + 11 )² + ( - 3 - 5 )² = 4 ² + ( - 8 )² = 16 + 64 = 80
c'est un carré
côté = √80 = 4 √5
aire = ( 4 √5) )² = 80