The coordinates of the vertices of △def are d(−4, 1) , e(3, −1) , and f(−1, −4) . which statement correctly describes whether △def is a right triangle? △def is a right triangle because de¯¯¯¯¯ is perpendicular to df¯¯¯¯¯ . △def is a right triangle because df¯¯¯¯¯ is perpendicular to ef¯¯¯¯¯ . △def is not a right triangle because no two sides are perpendicular. △def is a right triangle because de¯¯¯¯¯ is perpendicular to ef¯¯¯¯¯ .