AB = radical (XB - CA)^2+(YB-YA) ^2
AB = radical (5-2)^2 + (0-0)^2
AB = radical 3^2 +0^2
AB = radical 9
AB = 3
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BC = radical (XB-XC)^2+(YB-YC) ^2
BC = radical [5-(-1)]^2 +(0-0)^2
BC = radical 6^2 + 0^2
BC = radical 36
BC = 6
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AC = radical (XA-XC)^2+(XC-XA) ^2
AC = radical [2-(-1)]^2 + (0-0)^2
AC = radical 3^2 +0^2
AC = radical 9
AC = 3
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Sper ca te-am ajutat :)