Chứng minh rằng các đường trung tuyến của tam giác chia tam giác thành 6 phần có diện tích bằng nhau. Mn giúp mik vsss, mik đang cần gấp giải nhanh+đúng sẽ vote. cứuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu