Question

In reperul cartezian xOy se considera punctele a(1,2) b(5,2) si c(3,-1).Sa se calculeze perimetrul triunghiului ABC

Answer 1

$AB= \sqrt{(X _{B}-X _{A}) ^{2} +(Y _{B}-Y _{A}) ^{2} }$
$AB= \sqrt{(5-1) ^{2}+(2-2) ^{2} } =\ \textgreater \ AB=4 cm$
$BC= \sqrt{(3-5) ^{2}+(-1-2) ^{2} } = \sqrt{4+9} =\ \textgreater \ BC= \sqrt{13} cm$
$AC= \sqrt{(3-1) ^{2}+(-1-2) ^{2} } = \sqrt{4+9} =\ \textgreater \ AC= \sqrt{13} cm$
Perim.=4+2√13
          =2(2+√13) cm