綾 2年以上以前 a^2 + b^2 = 13*r^2 a^2 + c^2 = 10*r^2 b^2 + c^2 = 5*r^2 ———————————— a^2 + b^2 + c^2 = (13+10+5)*r^2/2 = 14*r^2 a^2 = 9*r^2 => a = 3r b^2 = 4*r^2 => b = 2r c^2 = 1*r^2 => c = 1r a : b : c = 3 : 2 : 1 留言