bonjour
( AB)² = ( 2 - 6 )² + ( - 3 - 5 )² = ( - 4 )² + ( - 8 )² = 16 + 64 = 80
( BC)² = ( - 4 - 2 )² + ( 0 + 3 )² = ( - 6 )² + 3 ² = 36 + 9 = 45
(AC)² = ( - 4 - 6 )² + ( 0 - 5 )² = ( - 10 )² + ( - 5 )² = 100 + 25 = 125
80 + 45 = 125 , le triangle est rectangle
AB = √80 = 4 √5
BC = √45 = 3 √5
AC = √125 = 5 √5
P = 4 √5 + 3 √5 + 5 √5 = 12 √5
A = ( 4 √5 * 3 √5) / 2 = 12 √25 /2 = 60/2 = 30
