не 2/3, а 3/2
ma^2 = (a/2)^2+b^2;
mb^2 = (b/2)^2+a^2;
mc = c/2; mc^2 = c^2/4
ma^2 + mb^2 + mc^2 = a^2 + b^2/4 + b^2 + a^2/4 + c^2/4 =
= c^2*(1 + 1/4 + 1/4) = c^2*3/2;
не 2/3, а 3/2
ma^2 = (a/2)^2+b^2;
mb^2 = (b/2)^2+a^2;
mc = c/2; mc^2 = c^2/4
ma^2 + mb^2 + mc^2 = a^2 + b^2/4 + b^2 + a^2/4 + c^2/4 =
= c^2*(1 + 1/4 + 1/4) = c^2*3/2;