What shape has 2 fewer sides than a Pentagon

A pentagon has 5 sides.  We are looking for a 3-sided shape, which would be a triangle.  There are many types of triangles: equilateral (all sides same length, all angles same measurement), isosceles (2 sides same length, 2 angles same measure), scalene (no sides same length, no angles same measure), obtuse (one angle greater than 90°), acute (all angles less than 90°), and right (one angle is 90°).