Mathematics - Properties of Triangle Question with Solution | TestHub

E,F are the midpoints of BD,DC; with D midpoint BC, E,D,F are equally spaced along BC and ED=a/4. Parallelogram/median identity $m{2}^2$+$m{3}^2$=2($m{1}^2$+$E{D}^2$)=$2m{1}^2$+$a^2$/8. Thus $a^2$/8=$m{2}^2$+$m{3}^2$-$2m{1}^2$.