Bonjour,
AB = d(-14;-1/2)
[tex]| - 14 - ( - \frac{1}{2}) | \\ = | - 14 + \frac{1}{2} | \\ = | \frac{ - 28 + 1}{2} | \\ = | - \frac{27}{2} | \\ = \frac{27}{2} \\ = 13.5[/tex]
BD = d(-1/2;1/3)
[tex]| - \frac{1}{2} - \frac{1}{3} | \\ = | - \frac{3 + 2}{6} | \\ = | - \frac{5}{6} | \\ = \frac{5}{6}[/tex]
BC = d(-1/2;7)
[tex]| - \frac{1}{2} - 7| \\ = | - \frac{1 + 14}{2} | \\ = | - \frac{15}{2} | \\ = \frac{15}{2} \\ = 7.5[/tex]
CD = d(7;1/3)
[tex]|7 - \frac{1}{3} | \\ = | \frac{21 - 1}{3} | \\ = | \frac{20}{3} | \\ = \frac{20}{3}[/tex]