The given statement can be written in five different ways as follows,
(i) A triangle is equiangular implies that it is an obtuse-angled triangle.
(ii) A triangle is equiangular only if it is an obtuse-angled triangle.
(iii) For a triangle to be equiangular it is necessary that the triangle is an obtuse-angled triangle.
(iv) For a triangle to be an obtuse-angled triangle it is sufficient that the triangle is equiangular.
(v) If a triangle is not an obtuse-angled triangle then the triangle is not equiangular.