If ABC is a right triangle right-angled at B and M, N are the mid-points of AB and BC respectively, then 4 (AN2 + CM2) =

Given ABC is a right triangle right-angled at B and M, N are mid-points of AB and BC respectively.



M is the mid-point of AB.



And N is the mid-point of BC.



Now,


AN2 + CM2 = (AB2 + ( �BC)2) + (( �AB)2 + BC2)


= AB2 + �BC2 + 1/4 AB2 + BC2


= 5/4 (AB2 + BC2)


4 (AN2 + CM2) = 5AC2


Hence proved.

1