Triangles 
 equilateral triangle 
 isosceles triangle 
 scalene triangle 
 all sides are equal
 always
 sometimes
 never
 all angles are equal
 always
 sometimes
 never
 exactly two sides are equal
 never
 always
 never
 one right angle
 never
 sometimes
 sometimes
 obtuse triangle
 never
 sometimes
 sometimes
 acute triangle
 sometimes
 sometimes
 sometimes