AB=√(4+1)2+(0+1)2=√26 BC=√(3+1)2+(5+1)2=√52 CA=√(4−3)2+(0−5)2=√26 In isosceles triangle side AB=CA For right angled triangle, BC2=AB2+AC2 So, here BC=√52 or BC2=52 or (√26)2+(√26)2=52 So, the given triangle is right angled and also isosceles.