Step 1 :a. False: An obtuse triangle has one obtuse angle and two acute angles.
Step 2 :b. False: A scalene triangle has all sides of different lengths, while an isosceles triangle has at least two sides of equal length.
Step 3 :c. True: Equilateral triangles have all sides equal, and all angles measure \(60^\circ\), which are acute angles.
Step 4 :d. True: Isosceles triangles may be equilateral, as the requirement for an isosceles triangle is to have at least two sides equal.
Step 5 :e. True: Right triangles can be scalene (e.g. 3-4-5 triangle) or isosceles (e.g. \(1-1-\sqrt{2}\) triangle).