Răspuns:
Explicație pas cu pas:
a) A(2, 5), B(1, 3), C(-3, 2)
AB = √[(2 - 1)^2 + (5 - 3)^2] = √(1 + 4) = √5
AC = √[(2 + 3)^2 + (5 - 2)^2] = √(25 + 9) = √34
BC = √[(1 + 3)^2 + (3 - 2)^2] = √(16 + 1) = √17
√5 + √17 = √34 fals
____________
b) A(4, 7), B(0, 4), C(-2, √4)
√4 = 2
A(4, 7), B(0, 4), C(-2, 2)
AB = √[(4 - 0)^2 + (7 - 4)^2] = √(16 + 9) = √25 = 5
AC = √[(4 + 2)^2 + (7 - 2)^2] = √(36 + 25) = √61
BC = √[(0 + 2)^2 + (4 - 2)^2] = √(4 + 4) = √8
5 + √8 = √61 fals