a)AB=rad[(3-1)^2 + (2-8)^2]
AB=rad(4+36)
AB=rad40=2rad10
BC=rad[(9-3)^2 + (4-2)^2]
BC=rad(36+4)
BC=rad40=2rad10
=>tr.ABC este isoscel
b)AB=rad[(-12+10)^2 + (30+4)^2]
AB=rad(4+1156)
AB=rad1160=2rad290
BC=rad[(0+12)^2 + (0-30)^2]
BC=rad(144+900)
BC=rad1044=6rad29
AC=rad[(0+10)^2 + (0+4)^2]
AC=rad(100+16)
AC=rad116
AC=2rad29
AB^2 =? AC^2 + BC^2 (T.Pitagora)
1160=? 116+1044
1160=1160 =>tr.ABC este dreptunghic
